50278 + Interview Questions in Physics

1.	Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :
Answer» Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :

1.

Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :

Answer»

Figure below shows two paths that may be taken by a gas to go from a state A to a state C.

In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :

Discussion

2.	The velocity of light in air is 3×108 m/s and in a medium is √3×108 m/s. The Brewster’s angle of the medium is
Answer» The velocity of light in air is $3 \times 10^{8}$ m/s and in a medium is $\sqrt{3} \times 10^{8}$ m/s. The Brewster’s angle of the medium is

Discussion

3.	A mass of 6×1024 kg (equal to the mass of the earth) is to be compressed in a sphere in such a way that the escape elocity from its surface is 3×108 m s−1 What should be the radius of the sphere?
Answer» A mass of $6 \times 10^{24}$ kg (equal to the mass of the earth) is to be compressed in a sphere in such a way that the escape elocity from its surface is $3 \times 10^{8}$ m $s^{- 1}$ What should be the radius of the sphere?

Discussion

4.	Explain clearly the function and working of p-n-p transistor and n-p-n transistor .
Answer» Explain clearly the function and working of p-n-p transistor and n-p-n transistor .

Discussion

5.	Two coherent light sources S1 and S2 (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be
Answer» Two coherent light sources S₁ and S₂ (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be

Discussion

6.	A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure. The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the right by 10 cm so that the joint is placed on the pulley, what will be the minimum frequency at which the heavy string can resonate?
Answer» A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure. The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the right by 10 cm so that the joint is placed on the pulley, what will be the minimum frequency at which the heavy string can resonate?

6.

A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure. The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the right by 10 cm so that the joint is placed on the pulley, what will be the minimum frequency at which the heavy string can resonate?

Answer»

A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in figure. The thread goes over a fixed pulley and supports a weight to produce a tension. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the right by 10 cm so that the joint is placed on the pulley, what will be the minimum frequency at which the heavy string can resonate?

Discussion

7.	Two balls each of mass 1 kg are connected to both ends of a uniform circular rod of mass 5 kg and length 2 m. Find the moment of inertia of the system about an axis passing through the middle of the rod and perpendicular to the length of the rod.
Answer» Two balls each of mass $1 kg$ are connected to both ends of a uniform circular rod of mass $5 kg$ and length $2 m$ . Find the moment of inertia of the system about an axis passing through the middle of the rod and perpendicular to the length of the rod.

Discussion

8.	The potential energy of a system is represented as shown in the figure. The force acting on the system will be represented by
Answer» The potential energy of a system is represented as shown in the figure. The force acting on the system will be represented by

8.

The potential energy of a system is represented as shown in the figure. The force acting on the system will be represented by

Answer»

The potential energy of a system is represented as shown in the figure. The force acting on the system will be represented by

Discussion

9.	A uniform electric field →E= aˆi+bˆj+cˆk intersects a surface of area A. What is the flux through this area, if surface lies in xy plane?
Answer» A uniform electric field $\to E = a ˆ i + b ˆ j + c ˆ k$ intersects a surface of area $A$ . What is the flux through this area, if surface lies in $x y$ plane?

Discussion

10.	A particle of mass m is attached to one end of a weightless and inextensible string of length L. The particle is on a smooth horizontal table. The string passes through a hole in the table and to its other end is attached a small particle of equal mass m. The system is set in motion with the first particle describing a circle on the table with constant angular velocity ω1 and the second particle moving in the horizontal circle as a conical pendulum with constant angular velocity ω2. Then ω22:ω21= [Take r1=1 m, L=3 m]
Answer» A particle of mass $m$ is attached to one end of a weightless and inextensible string of length $L$ . The particle is on a smooth horizontal table. The string passes through a hole in the table and to its other end is attached a small particle of equal mass $m$ . The system is set in motion with the first particle describing a circle on the table with constant angular velocity $ω_{1}$ and the second particle moving in the horizontal circle as a conical pendulum with constant angular velocity $ω_{2}$ . Then $ω_{2}^{2} : ω_{1}^{2} =$ [Take $r_{1} = 1 m, L = 3 m$ ]

Discussion

11.	For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and internal resistance of the cell is E and r , respectively.
Answer» For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and internal resistance of the cell is E and r , respectively.

11.

For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and internal resistance of the cell is E and r , respectively.

Answer»

For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and internal resistance of the cell is E and r , respectively.

Discussion

12.	A copper rod of length L and mass m carrying current I flowing inwards and perpendicular to the plane(as shown in the figure) , is placed on a fixed smooth inclined plane of inclination θ . If a vertically upward magnetic field →B exists in this region, find the magnitude of the magnetic field →B for which the copper rod slides down the inclined plane with a constant speed.
Answer» A copper rod of length $L$ and mass $m$ carrying current $I$ flowing inwards and perpendicular to the plane(as shown in the figure) , is placed on a fixed smooth inclined plane of inclination $θ$ . If a vertically upward magnetic field $\to B$ exists in this region, find the magnitude of the magnetic field $\to B$ for which the copper rod slides down the inclined plane with a constant speed.

12.

A copper rod of length L and mass m carrying current I flowing inwards and perpendicular to the plane(as shown in the figure) , is placed on a fixed smooth inclined plane of inclination θ . If a vertically upward magnetic field →B exists in this region, find the magnitude of the magnetic field →B for which the copper rod slides down the inclined plane with a constant speed.

Answer»

A copper rod of length $L$ and mass $m$ carrying current $I$ flowing inwards and perpendicular to the plane(as shown in the figure) , is placed on a fixed smooth inclined plane of inclination $θ$ . If a vertically upward magnetic field $\to B$ exists in this region, find the magnitude of the magnetic field $\to B$ for which the copper rod slides down the inclined plane with a constant speed.

Discussion

13.	Water from a pipe is coming at a rate of 100 litres per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of (density of water =1000 kg/m3, coefficient of viscosity of water =1 mPa).
Answer» Water from a pipe is coming at a rate of $100 l i t r e s$ per minute. If the radius of the pipe is $5 c m$ , the Reynolds number for the flow is of the order of (density of water $= 1000 k g / m^{3}$ , coefficient of viscosity of water $= 1 m P a$ ).

Discussion

14.	What is the de Broglie wavelength of an electron with a kinetic energy of 120 eV? (Given: h=6.63×10−34 Js,me=9.11×10−31kg,e=1.6×10−19coulomb
Answer» What is the de Broglie wavelength of an electron with a kinetic energy of $120 eV$ ? (Given: $h = 6.63 \times 10^{- 34} Js, m_{e} = 9.11 \times 10^{- 31} kg, e = 1.6 \times 10^{- 19} coulomb$

Discussion

15.	A sample of gas is filled in a closed vessel, if temperature of gas is increased by 2∘K and pressure by 0.2 %, then initial temperature of gas wil be
Answer» A sample of gas is filled in a closed vessel, if temperature of gas is increased by $2^{\circ} K$ and pressure by $0.2$ %, then initial temperature of gas wil be

Discussion

16.	A small plane mirror is placed at the centre of a spherical screen of radius R. A beam of light is falling on the mirror. If the mirror makes n revolution per second, the speed of the spot of light on the screen after reflection from the mirror will be
Answer» A small plane mirror is placed at the centre of a spherical screen of radius R. A beam of light is falling on the mirror. If the mirror makes n revolution per second, the speed of the spot of light on the screen after reflection from the mirror will be

Discussion

17.	An ideal diatomic gas under goes a process in which it internal energy changes with volume as given U=cV25 where c is constant. Find the ratio of molar heat capacity of the process to universal gas constant R.___
Answer» An ideal diatomic gas under goes a process in which it internal energy changes with volume as given $U = c V^{\frac{2}{5}}$ where c is constant. Find the ratio of molar heat capacity of the process to universal gas constant R.___

Discussion

18.	In Young’s double-slit experiment, the intensity at a point where the path difference is λ6 (λ being the wavelength of the light used) is I. If I0 denotes the maximum intensity, then II0 is equal to
Answer» In Young’s double-slit experiment, the intensity at a point where the path difference is $\frac{λ}{6}$ ( $λ$ being the wavelength of the light used) is I. If $I_{0}$ denotes the maximum intensity, then $\frac{I}{I_{0}}$ is equal to

Discussion

19.	A wire of negligible mass and length l is stretched between two fixed points P and Q. The wire suffers from a tension T when a mass m is attached to the wire. Distance of this mass from fix point P is a and from Q is b. The attachment of mass to the stretched wire sets it into oscillations of small amplitude. Since the amplitude is small, the transverse movement of R is small so the change in length of the wire can be ignored. Thus tension in the wire can be taken as practically same as T itself. The time period of linear vibratory motion of the mass can be given by T=2πω, where ω is a constant of SHM. Angular frequency of SHM of mass m is
Answer» A wire of negligible mass and length l is stretched between two fixed points P and Q. The wire suffers from a tension T when a mass m is attached to the wire. Distance of this mass from fix point P is a and from Q is b. The attachment of mass to the stretched wire sets it into oscillations of small amplitude. Since the amplitude is small, the transverse movement of R is small so the change in length of the wire can be ignored. Thus tension in the wire can be taken as practically same as T itself. The time period of linear vibratory motion of the mass can be given by $T = \frac{2 π}{ω}$ , where $ω$ is a constant of SHM. Angular frequency of SHM of mass m is

19.

A wire of negligible mass and length l is stretched between two fixed points P and Q. The wire suffers from a tension T when a mass m is attached to the wire. Distance of this mass from fix point P is a and from Q is b. The attachment of mass to the stretched wire sets it into oscillations of small amplitude. Since the amplitude is small, the transverse movement of R is small so the change in length of the wire can be ignored. Thus tension in the wire can be taken as practically same as T itself. The time period of linear vibratory motion of the mass can be given by T=2πω, where ω is a constant of SHM. Angular frequency of SHM of mass m is

Answer»

A wire of negligible mass and length l is stretched between two fixed points P and Q. The wire suffers from a tension T when a mass m is attached to the wire. Distance of this mass from fix point P is a and from Q is b. The attachment of mass to the stretched wire sets it into oscillations of small amplitude. Since the amplitude is small, the transverse movement of R is small so the change in length of the wire can be ignored. Thus tension in the wire can be taken as practically same as T itself. The time period of linear vibratory motion of the mass can be given by $T = \frac{2 π}{ω}$ , where $ω$ is a constant of SHM.

Angular frequency of SHM of mass m is

Discussion

20.	The magnitude of magnetic moment of the current loop shown in the figure is
Answer» The magnitude of magnetic moment of the current loop shown in the figure is

Discussion

21.	Three large plates are arranged as shown. How much charge will flow through the key k if it is closed?
Answer» Three large plates are arranged as shown. How much charge will flow through the key k if it is closed?

21.

Three large plates are arranged as shown. How much charge will flow through the key k if it is closed?

Answer»

Three large plates are arranged as shown. How much charge will flow through the key k if it is closed?

Discussion

22.	The difference between the apparent frequency of a source of sound as perceived by the stationary observer during its approach and recession is 2% of the frequency of the source. If the speed of sound in air is 300ms−1 the velocity of the source is
Answer» The difference between the apparent frequency of a source of sound as perceived by the stationary observer during its approach and recession is 2 $%$ of the frequency of the source. If the speed of sound in air is $300 m s^{- 1}$ the velocity of the source is

Discussion

23.	In the following equation x, t and F represent respectively displacement, time and force: F=a+bt+1c+dx+A sin (ωt+ϕ). The dimensional formula for 'Ad' is
Answer» In the following equation x, t and F represent respectively displacement, time and force: $F = a + b t + \frac{1}{c + d x} + A s i n (ω t + ϕ)$ . The dimensional formula for 'Ad' is

Discussion

24.	If VD=12 volt & VE=8 volt then
Answer» If $V_{D} = 12$ volt & $V_{E} = 8$ volt then

Discussion

25.	The plates S and T of an uncharged parallel plate capacitor are connected across a battery. The battery is then disconnected and the charged plates are now connected in a system as shown in the figure. The system shown is in equilibrium. All the strings are insulating and massless. The magnitude of charge on one of the capacitor plates is: [Area of plates = A]
Answer» The plates S and T of an uncharged parallel plate capacitor are connected across a battery. The battery is then disconnected and the charged plates are now connected in a system as shown in the figure. The system shown is in equilibrium. All the strings are insulating and massless. The magnitude of charge on one of the capacitor plates is: [Area of plates = A]

Discussion

26.	A compound microscope is used to enlarge an object kept at a distance of 0.03 m from it's objective which consists of several convex lenses in contact and has focal length 0.02 m. If a lens of focal length 0.1 m is removed from the objective, then to refocus the image the eye-piece of the microscope must be moved by (in cm)
Answer» A compound microscope is used to enlarge an object kept at a distance of 0.03 $m$ from it's objective which consists of several convex lenses in contact and has focal length $0.02 m$ . If a lens of focal length 0.1 $m$ is removed from the objective, then to refocus the image the eye-piece of the microscope must be moved by (in cm)

Discussion

27.	An LCR circuit with 100Ω resistance is connected to an AC source of 200 V and angular frequency of 300 rad/s. When only capacitor is removed, current lags behind the voltage by 60∘. When only inductor is removed, current leads voltage by 60∘, then rms current in LCR circuit is
Answer» An LCR circuit with $100 Ω$ resistance is connected to an AC source of 200 V and angular frequency of 300 rad/s. When only capacitor is removed, current lags behind the voltage by $60^{\circ}$ . When only inductor is removed, current leads voltage by $60^{\circ}$ , then rms current in LCR circuit is

Discussion

28.	In the given figure, radius of conducting shell 'A', 'B' and 'C' are R, 2R and 3R respectively. Charge on conducting shell 'A', 'B' and 'C' are 3Q, -2Q and Q respectively. Charge flown from 'A' to 'C', when switch 'S' is closed is
Answer» In the given figure, radius of conducting shell 'A', 'B' and 'C' are $R$ , 2 $R$ and 3 $R$ respectively. Charge on conducting shell 'A', 'B' and 'C' are 3 $Q$ , -2 $Q$ and $Q$ respectively. Charge flown from 'A' to 'C', when switch 'S' is closed is

Discussion

29.	A capacitor of capacity 2μF is charged to a potential difference of 12 V. It is then connected across an inductor of inductance 6μH. What is the current (in A) in the circuit at a time when the potential difference across the capacitor is 6.0 V?
Answer» A capacitor of capacity $2 μ F$ is charged to a potential difference of 12 V. It is then connected across an inductor of inductance $6 μ H$ . What is the current (in A) in the circuit at a time when the potential difference across the capacitor is 6.0 V?

Discussion

30.	A P-type semiconductor has acceptor levels 57 meV above the valence band. The maximum wavelength of light required to create a hole is (Planck’s constant h=6.6×10−34 J-s)
Answer» A P-type semiconductor has acceptor levels 57 meV above the valence band. The maximum wavelength of light required to create a hole is (Planck’s constant $h = 6.6 \times 10^{- 34}$ J-s)

Discussion

31.	The magnetic field at the centre of an equilateral triangular loop of side 2L and carrying a current i is
Answer» The magnetic field at the centre of an equilateral triangular loop of side $2 L$ and carrying a current $i$ is

Discussion

32.	If velocity V, acceleration A and force F are taken as fundamental quantities, then the dimensional formula of angular momentum in terms of V, A and F will be
Answer» If velocity $V$ , acceleration $A$ and force $F$ are taken as fundamental quantities, then the dimensional formula of angular momentum in terms of $V, A$ and $F$ will be

Discussion

33.	Two balls are thrown with the same speed but making complementary angle with the horizontal. If the angle of projection of one is 60∘ and its maximum height is h, then the maximum height of the other will be
Answer» Two balls are thrown with the same speed but making complementary angle with the horizontal. If the angle of projection of one is $60^{\circ}$ and its maximum height is $h$ , then the maximum height of the other will be

Discussion

34.	Two unequal masses of 1 kg and 2 kg are connected by an inextensible light string passing over a smooth pulley as shown in the figure. A force F=20 N is applied on 1 kg block. Find the acceleration of either block. (g=10m/s2) in m/s2
Answer» Two unequal masses of $1 k g$ and $2 k g$ are connected by an inextensible light string passing over a smooth pulley as shown in the figure. A force $F = 20 N$ is applied on $1 k g$ block. Find the acceleration of either block. $(g = 10 m / s^{2})$ in $m / s^{2}$

Discussion

35.	A bullet with muzzle velocity 500 m/s is to be shot at a target 1000 m away in the same horizontal line. At what height above the target, a rifle must be aimed so that the bullet will hit the target ?
Answer» A bullet with muzzle velocity $500 m/s$ is to be shot at a target $1000 m$ away in the same horizontal line. At what height above the target, a rifle must be aimed so that the bullet will hit the target ?

Discussion

36.	What is Newton's cradle?
Answer» What is Newton's cradle?

Discussion

37.	The graph between u and V for a convex mirror is given by
Answer» The graph between $u$ and $V$ for a convex mirror is given by

Discussion

38.	A n-type silicon sample of width 4×10−3 m, thickness 25×10−5 m and length 6×10−2 m carries a current of 4.8 mA when a voltage is applied across the length of the sample. If the free electron density is 1022 m−3, how much time does it take for the electrons to travel the full length of the sample? Given that charge on an electron, e=1.6×10−19 C .
Answer» A n-type silicon sample of width $4 \times 10^{- 3} m$ , thickness $25 \times 10^{- 5} m$ and length $6 \times 10^{- 2} m$ carries a current of 4.8 mA when a voltage is applied across the length of the sample. If the free electron density is $10^{22} m^{- 3},$ how much time does it take for the electrons to travel the full length of the sample? Given that charge on an electron, $e = 1.6 \times 10^{- 19} C$ .

Discussion

39.	A uniform cylinder has a radius R and length L. If the moment of inertia of this cylinder about an axis passing through its centre and normal to its circular face is equal to the moment of inertia of the same cylinder about an axis passing through its centre and normal to its length; then
Answer» A uniform cylinder has a radius $R$ and length $L$ . If the moment of inertia of this cylinder about an axis passing through its centre and normal to its circular face is equal to the moment of inertia of the same cylinder about an axis passing through its centre and normal to its length; then

Discussion

40.	A boat which has a speed of 5 km/h in still water crosses a river of width 1 km along the shortest possible path in 15 min. The velocity of the river water in km/h is
Answer» A boat which has a speed of $5 km/h$ in still water crosses a river of width $1 km$ along the shortest possible path in $15 min$ . The velocity of the river water in $km/h$ is

Discussion

41.	If the ratio of radii of two spheres of same material is 1:4, then the ratio of their heat capacity will be
Answer» If the ratio of radii of two spheres of same material is $1 : 4$ , then the ratio of their heat capacity will be

Discussion

42.	Question 30 Draw ray diagrams showing the image formation by a concave mirror when an object is placed (a) between pole and focus of the mirror (b) between focus and centre of curvature of the mirror (c) at centre of curvature of the mirror (d) a little beyond centre of curvature of the mirror (e) at infinity
Answer» Question 30 Draw ray diagrams showing the image formation by a concave mirror when an object is placed (a) between pole and focus of the mirror (b) between focus and centre of curvature of the mirror (c) at centre of curvature of the mirror (d) a little beyond centre of curvature of the mirror (e) at infinity

Discussion

43.	A cyclic process for 1 mole of an ideal gas is shown in the V−T diagram. The work done in AB,BC and CA respectively is
Answer» A cyclic process for $1 mole$ of an ideal gas is shown in the $V - T$ diagram. The work done in $A B, B C$ and $C A$ respectively is

Discussion

44.	A smooth uniform rod of length L and mass M has two identical beads of negligible size, each of mass m, which can slide freely along the rod. Initially, the two beads are at the centre of the rod and the system is rotating with angular velocity ω0 about an axis perpendicular to the rod and passing through the mid-point C of the rod. There are no external forces. When the beads reach the ends of the rod, then angular velocity of the system is
Answer» A smooth uniform rod of length $L$ and mass $M$ has two identical beads of negligible size, each of mass $m$ , which can slide freely along the rod. Initially, the two beads are at the centre of the rod and the system is rotating with angular velocity $ω_{0}$ about an axis perpendicular to the rod and passing through the mid-point $C$ of the rod. There are no external forces. When the beads reach the ends of the rod, then angular velocity of the system is

Discussion

45.	The time constant of a circuit where a capacitor C=10 nF is being charged connected to a cell through a resistor of 10 Ω is.
Answer» The time constant of a circuit where a capacitor $C = 10 n F$ is being charged connected to a cell through a resistor of $10 Ω$ is.

Discussion

46.	The point from where a ball of mass 2 kg is projected is taken as the origin of the co-ordinate axes. The x and y components of its displacement are given by x=6t and y=8t−5t2. Find the average force on it from t=0 s to t=2 s seconds.
Answer» The point from where a ball of mass $2 kg$ is projected is taken as the origin of the co-ordinate axes. The $x$ and $y$ components of its displacement are given by $x = 6 t$ and $y = 8 t - 5 t^{2}$ . Find the average force on it from $t = 0 s$ to $t = 2 s$ seconds.

Discussion

47.	Water is flowing continuously from a tap having an internal diameter 8×10−3 m. The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance 2×10−1 m below the tap is close to
Answer» Water is flowing continuously from a tap having an internal diameter $8 \times 10^{- 3} m$ . The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance $2 \times 10^{- 1} m$ below the tap is close to

Discussion

48.	Find the ratio of diameter of the sun to the diameter of the earth, if the diameter of the sun and earth are 1.4×109 m and 1.275×107 m respectively.
Answer» Find the ratio of diameter of the sun to the diameter of the earth, if the diameter of the sun and earth are $1.4 \times 10^{9}$ m and $1.275 \times 10^{7}$ m respectively.

Discussion

49.	A body falling freelynfromfa given height H Hits an inclined plane in its path at a height h. As a result of this impact the direction of the velocity of the body becomes horizontal. For what value of h/H, the body will take the maximum time to reach the ground.
Answer» A body falling freelynfromfa given height H Hits an inclined plane in its path at a height h. As a result of this impact the direction of the velocity of the body becomes horizontal. For what value of h/H, the body will take the maximum time to reach the ground.

Discussion

50.	Consider a uniform electric field E=3×103^i N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis?
Answer» Consider a uniform electric field $E = 3 \times 10^{3}^i N / C$ . (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :

The velocity of light in air is 3×108 m/s and in a medium is √3×108 m/s. The Brewster’s angle of the medium is

A mass of 6×1024 kg (equal to the mass of the earth) is to be compressed in a sphere in such a way that the escape elocity from its surface is 3×108 m s−1 What should be the radius of the sphere?

Explain clearly the function and working of p-n-p transistor and n-p-n transistor .

Two coherent light sources S1 and S2 (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be

Two balls each of mass 1 kg are connected to both ends of a uniform circular rod of mass 5 kg and length 2 m. Find the moment of inertia of the system about an axis passing through the middle of the rod and perpendicular to the length of the rod.

The potential energy of a system is represented as shown in the figure. The force acting on the system will be represented by

A uniform electric field →E= aˆi+bˆj+cˆk intersects a surface of area A. What is the flux through this area, if surface lies in xy plane?

For a cell, a graph is plotted between the potential difference V across the terminals of the cell and the current I drawn from the cell. The e.m.f and internal resistance of the cell is E and r , respectively.

Water from a pipe is coming at a rate of 100 litres per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of (density of water =1000 kg/m3, coefficient of viscosity of water =1 mPa).

What is the de Broglie wavelength of an electron with a kinetic energy of 120 eV? (Given: h=6.63×10−34 Js,me=9.11×10−31kg,e=1.6×10−19coulomb

A sample of gas is filled in a closed vessel, if temperature of gas is increased by 2∘K and pressure by 0.2 %, then initial temperature of gas wil be

A small plane mirror is placed at the centre of a spherical screen of radius R. A beam of light is falling on the mirror. If the mirror makes n revolution per second, the speed of the spot of light on the screen after reflection from the mirror will be

An ideal diatomic gas under goes a process in which it internal energy changes with volume as given U=cV25 where c is constant. Find the ratio of molar heat capacity of the process to universal gas constant R.___

In Young’s double-slit experiment, the intensity at a point where the path difference is λ6 (λ being the wavelength of the light used) is I. If I0 denotes the maximum intensity, then II0 is equal to

The magnitude of magnetic moment of the current loop shown in the figure is

Three large plates are arranged as shown. How much charge will flow through the key k if it is closed?

The difference between the apparent frequency of a source of sound as perceived by the stationary observer during its approach and recession is 2% of the frequency of the source. If the speed of sound in air is 300ms−1 the velocity of the source is

In the following equation x, t and F represent respectively displacement, time and force: F=a+bt+1c+dx+A sin (ωt+ϕ). The dimensional formula for 'Ad' is

If VD=12 volt &amp; VE=8 volt then

An LCR circuit with 100Ω resistance is connected to an AC source of 200 V and angular frequency of 300 rad/s. When only capacitor is removed, current lags behind the voltage by 60∘. When only inductor is removed, current leads voltage by 60∘, then rms current in LCR circuit is

In the given figure, radius of conducting shell 'A', 'B' and 'C' are R, 2R and 3R respectively. Charge on conducting shell 'A', 'B' and 'C' are 3Q, -2Q and Q respectively. Charge flown from 'A' to 'C', when switch 'S' is closed is

A capacitor of capacity 2μF is charged to a potential difference of 12 V. It is then connected across an inductor of inductance 6μH. What is the current (in A) in the circuit at a time when the potential difference across the capacitor is 6.0 V?

A P-type semiconductor has acceptor levels 57 meV above the valence band. The maximum wavelength of light required to create a hole is (Planck’s constant h=6.6×10−34 J-s)

The magnetic field at the centre of an equilateral triangular loop of side 2L and carrying a current i is

If velocity V, acceleration A and force F are taken as fundamental quantities, then the dimensional formula of angular momentum in terms of V, A and F will be

Two balls are thrown with the same speed but making complementary angle with the horizontal. If the angle of projection of one is 60∘ and its maximum height is h, then the maximum height of the other will be

Two unequal masses of 1 kg and 2 kg are connected by an inextensible light string passing over a smooth pulley as shown in the figure. A force F=20 N is applied on 1 kg block. Find the acceleration of either block. (g=10m/s2) in m/s2

A bullet with muzzle velocity 500 m/s is to be shot at a target 1000 m away in the same horizontal line. At what height above the target, a rifle must be aimed so that the bullet will hit the target ?

What is Newton's cradle?

The graph between u and V for a convex mirror is given by

A uniform cylinder has a radius R and length L. If the moment of inertia of this cylinder about an axis passing through its centre and normal to its circular face is equal to the moment of inertia of the same cylinder about an axis passing through its centre and normal to its length; then

A boat which has a speed of 5 km/h in still water crosses a river of width 1 km along the shortest possible path in 15 min. The velocity of the river water in km/h is

If the ratio of radii of two spheres of same material is 1:4, then the ratio of their heat capacity will be

A cyclic process for 1 mole of an ideal gas is shown in the V−T diagram. The work done in AB,BC and CA respectively is

The time constant of a circuit where a capacitor C=10 nF is being charged connected to a cell through a resistor of 10 Ω is.

The point from where a ball of mass 2 kg is projected is taken as the origin of the co-ordinate axes. The x and y components of its displacement are given by x=6t and y=8t−5t2. Find the average force on it from t=0 s to t=2 s seconds.

Water is flowing continuously from a tap having an internal diameter 8×10−3 m. The water velocity as it leaves the tap is 0.4 m/s. The diameter of the water stream at a distance 2×10−1 m below the tap is close to

Find the ratio of diameter of the sun to the diameter of the earth, if the diameter of the sun and earth are 1.4×109 m and 1.275×107 m respectively.

A body falling freelynfromfa given height H Hits an inclined plane in its path at a height h. As a result of this impact the direction of the velocity of the body becomes horizontal. For what value of h/H, the body will take the maximum time to reach the ground.

Consider a uniform electric field E=3×103^i N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane? (b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis?

If VD=12 volt & VE=8 volt then