50278 + Interview Questions in Physics

1.	In Young's double slit experiment the slits are 0.5 mm apart and the interference is observed on a screen at a distance of 100 cm from the slit. It is found that the 9th bright fringe is at a distance of 7.5 mm from the second dark fringe from the centre of the fringe pattern. The wavelength of the light used is
Answer» In Young's double slit experiment the slits are 0.5 mm apart and the interference is observed on a screen at a distance of 100 cm from the slit. It is found that the 9th bright fringe is at a distance of 7.5 mm from the second dark fringe from the centre of the fringe pattern. The wavelength of the light used is

Discussion

2.	A smooth piston of mass m and area of cross-section A is in equilibrium with the gas in the jar, when the pressure of the gas is P0. Find the angular frequency of oscillation of the piston, assuming adiabatic change of state of the gas.
Answer» A smooth piston of mass $m$ and area of cross-section $A$ is in equilibrium with the gas in the jar, when the pressure of the gas is $P_{0}$ . Find the angular frequency of oscillation of the piston, assuming adiabatic change of state of the gas.

Discussion

3.	A smooth ring of mass can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley and carries a block C of mass as shown below. As the ring starts sliding.
Answer» A smooth ring of mass can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley and carries a block C of mass as shown below. As the ring starts sliding.

Discussion

4.	A ball is dropped from a height. If the maximum percentage errors in measurement of the height and the time are e1 and e2 respectively, then maximum percentage error in the estimation of g is
Answer» A ball is dropped from a height. If the maximum percentage errors in measurement of the height and the time are $e_{1}$ and $e_{2}$ respectively, then maximum percentage error in the estimation of $g$ is

Discussion

5.	Two small objects are 15 m apart on the water surface of a lake. Each object pops up and down with a period of 4.5 second due to wave motion on water surface. When one object is at its highest point, the another one is at its lowest point. Consider that objects are always within a single cycle of wave, the speed of wave is (Assume transverse surface waves)
Answer» Two small objects are $15 m$ apart on the water surface of a lake. Each object pops up and down with a period of $4.5 second$ due to wave motion on water surface. When one object is at its highest point, the another one is at its lowest point. Consider that objects are always within a single cycle of wave, the speed of wave is (Assume transverse surface waves)

Discussion

6.	Velocity of the boat with respect to river (vb/r) is 10 m/s. It passes the river of width 36 m and reaches opposite shore at point R shown in the figure. If the velocity of the river is 3 m/s, find the time of the trip and drift of the boat.
Answer» Velocity of the boat with respect to river ( $v_{b / r}$ ) is $10 m / s$ . It passes the river of width $36 m$ and reaches opposite shore at point $R$ shown in the figure. If the velocity of the river is $3 m / s$ , find the time of the trip and drift of the boat.

Discussion

7.	A rectangular plate of sides a and b is suspended from a ceiling by two parallel strings of length L each (figure 12-E11). The separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute simple harmonic motion. Find the time period.
Answer» A rectangular plate of sides a and b is suspended from a ceiling by two parallel strings of length L each (figure 12-E11). The separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute simple harmonic motion. Find the time period.

7.

A rectangular plate of sides a and b is suspended from a ceiling by two parallel strings of length L each (figure 12-E11). The separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute simple harmonic motion. Find the time period.

Answer»

A rectangular plate of sides a and b is suspended from a ceiling by two parallel strings of length L each (figure 12-E11). The separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute simple harmonic motion. Find the time period.

Discussion

8.	A force f(bar)=5i(cap)–3j(cap)+2k(cap) moves a particle from r1(bar)=2i+7j+4k to r2=5i+2j+8k. Calculate the work done
Answer» A force f(bar)=5i(cap)–3j(cap)+2k(cap) moves a particle from r1(bar)=2i+7j+4k to r2=5i+2j+8k. Calculate the work done

Discussion

9.	The old gramophone record player spins the disc at a constant frequency of 75 Hz. Find the average angular velocity of the disk.
Answer» The old gramophone record player spins the disc at a constant frequency of $75 Hz$ . Find the average angular velocity of the disk.

Discussion

10.	Velocity-time graph of an object is given below. The corresponding displacement – time graph is:
Answer» Velocity-time graph of an object is given below. The corresponding displacement – time graph is:

10.

Velocity-time graph of an object is given below. The corresponding displacement – time graph is:

Answer»

Velocity-time graph of an object is given below. The corresponding displacement – time graph is:

Discussion

11.	A galvanometer of resistance 80 ohm, shunted by a resistance of 20 ohm is joined in series with a resistance of 200 ohm and cell of emf 1.5V What is the sensitivity of the galvanometer if it shows a deflection of 30 divisions.
Answer» A galvanometer of resistance 80 ohm, shunted by a resistance of 20 ohm is joined in series with a resistance of 200 ohm and cell of emf 1.5V What is the sensitivity of the galvanometer if it shows a deflection of 30 divisions.

Discussion

12.	Fluid used in the column is mercury. The pressure of the gas in the cylinder is : Given : Atmospheric pressure =1.01×105 N/m2, g=10 m/s2 and density of mercury =13600 kg/m3.
Answer» Fluid used in the column is mercury. The pressure of the gas in the cylinder is : Given : Atmospheric pressure $= 1.01 \times 10^{5} {N/m}^{2}, g = 10 {m/s}^{2}$ and density of mercury $= 13600 {kg/m}^{3}$ .

Discussion

13.	What is the voltage gain in a common emitter, where input resistance is 3Ω and the load resistance is 24Ω, β = 0.6
Answer» What is the voltage gain in a common emitter, where input resistance is 3Ω and the load resistance is 24Ω, β = 0.6

Discussion

14.	Water rises in a vertical capillary tube up to 2√2 cm. If the tube is inclined at an angle θ∘, the length of water risen in the tube is 4 cm. Find the value of θ.
Answer» Water rises in a vertical capillary tube up to $2 \sqrt{2} cm$ . If the tube is inclined at an angle $θ^{\circ}$ , the length of water risen in the tube is $4 cm$ . Find the value of $θ$ .

Discussion

15.	How do we know that when do we have to use dot product and cross product in a problem?
Answer» How do we know that when do we have to use dot product and cross product in a problem?

Discussion

16.	Λ of a M32 solution of a weak acid is 8 S cm2 mol−1 and the limiting molar conductivity is 400 S cm2 mol−1. Ka of the acid is:
Answer» $Λ$ of a $\frac{M}{32}$ solution of a weak acid is $8 S {cm}^{2} {mol}^{- 1}$ and the limiting molar conductivity is $400 S {cm}^{2} {mol}^{- 1}$ . $K_{a}$ of the acid is:

Discussion

17.	The values of L and R in LCR circuit are 1 mH and 10 Ω respectively. What is the value of its bandwidth?
Answer» The values of $L$ and $R$ in $L C R$ circuit are $1 m H$ and $10 Ω$ respectively. What is the value of its bandwidth?

Discussion

18.	Empirical formula = C2H4O n=2 (n=molecular mass ÷ emperical formula mass Emperical formula mass = 44 Molecular mass = 88) molecular formula = n × empirical formula = 2 × C2H4O = C4H8O2 but the book answer is given that C4H8O Which is correct ? If the book answer is correct , tell me how ?
Answer» Empirical formula = C₂H₄O n=2 (n=molecular mass ÷ emperical formula mass Emperical formula mass = 44 Molecular mass = 88) molecular formula = n × empirical formula = 2 × C₂H₄O = C₄H₈O₂ but the book answer is given that C₄H₈O Which is correct ? If the book answer is correct , tell me how ?

Discussion

19.	A vessel contains oil (density 0.8 g/cm2) over mercury (density 13.6 g/cm3). A homogeneous sphere floats with half its volume immersed in mercury and the other half in oil. The density of the material of the sphere in g/cm3 is
Answer» A vessel contains oil (density $0.8 {g/cm}^{2}$ ) over mercury (density $13.6 {g/cm}^{3}$ ). A homogeneous sphere floats with half its volume immersed in mercury and the other half in oil. The density of the material of the sphere in ${g/cm}^{3}$ is

Discussion

20.	Which out of electron and photon possess more energy for a given frequency? Can students contact on Monday?
Answer» Which out of electron and photon possess more energy for a given frequency? Can students contact on Monday?

Discussion

21.	When a system absorbs heat,the molecules start moving faster because kinetic energy increases,hence disorder increases. For the same amount of heat absorbed at lower temperature,the disorder is more than at higher temperature.why?explain.
Answer» When a system absorbs heat,the molecules start moving faster because kinetic energy increases,hence disorder increases. For the same amount of heat absorbed at lower temperature,the disorder is more than at higher temperature.why?explain.

Discussion

22.	A truck is moving with a constant velocity of 54 km/h. In which direction (angle with the direction of motion of truck) should a stone be projected up with a velocity of 20 m/s relative to truck, so that for a person standing on the earth stone appears to be at right angles to the truck ?
Answer» A truck is moving with a constant velocity of $54 km/h$ . In which direction (angle with the direction of motion of truck) should a stone be projected up with a velocity of $20 m/s$ relative to truck, so that for a person standing on the earth stone appears to be at right angles to the truck ?

Discussion

23.	A spring is cut in two halves. The spring constant of each half becomes
Answer» A spring is cut in two halves. The spring constant of each half becomes

Discussion

24.	Find the average force needed to accelerate a car weighing 500 kg from rest to 72 km/h in a distance of 25 m.
Answer» Find the average force needed to accelerate a car weighing 500 kg from rest to 72 km/h in a distance of 25 m.

Discussion

25.	In an atom, an electron is moving with the speed of 660 m/s have an accuracy of 0.005%. The minimum uncertainty with which the position of the electron can be located is: (h=6.6×10−34 J s;mass of electron,em=9×10−31 kg and π=3)
Answer» In an atom, an electron is moving with the speed of 660 m/s have an accuracy of 0.005%. The minimum uncertainty with which the position of the electron can be located is: $(h = 6.6 \times 10^{- 34} J s; mass of electron, e_{m} = 9 \times 10^{- 31} kg and π = 3)$

Discussion

26.	A photographic film is coated with a silver bromide layer. When light falls on this film, silver bromide molecules dissociate and the film records the light there. A minimum of 0.6 eV is needed to dissociate a silver bromide molecule. Find the maximum wavelength of light that can be recorded by the film.
Answer» A photographic film is coated with a silver bromide layer. When light falls on this film, silver bromide molecules dissociate and the film records the light there. A minimum of 0.6 eV is needed to dissociate a silver bromide molecule. Find the maximum wavelength of light that can be recorded by the film.

Discussion

27.	What is the gravitational pull between two electrons?
Answer» What is the gravitational pull between two electrons?

Discussion

28.	Each condenser in the figure shown has a capacity of 3 μF. The equivalent capacity between the terminals A and B is
Answer» Each condenser in the figure shown has a capacity of 3 μF. The equivalent capacity between the terminals A and B is

28.

Each condenser in the figure shown has a capacity of 3 μF. The equivalent capacity between the terminals A and B is

Answer»

Each condenser in the figure shown has a capacity of 3 μF. The equivalent capacity between the terminals A and B is

Discussion

29.	The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit. The current IZ through the Zener is
Answer» The reverse breakdown voltage of a Zener diode is $5.6 V$ in the given circuit. The current $I_{Z}$ through the Zener is

Discussion

30.	Find the number of photons emitted per second by a 24 W source of monochromatic light of wavelength 6600 ∘A :
Answer» Find the number of photons emitted per second by a 24 W source of monochromatic light of wavelength 6600 $^{\circ}$ :

Discussion

31.	A disc of mass m and radius R is resting on horizontal surface with coefficient of friction μ. If sudden velocity V0 (without any angular velocity) is imparted to disc then time after which disc starts pure rolling is
Answer» A disc of mass m and radius R is resting on horizontal surface with coefficient of friction $μ$ . If sudden velocity $V_{0}$ (without any angular velocity) is imparted to disc then time after which disc starts pure rolling is

Discussion

32.	A particle is projected from a horizontal plane (x-y plane) such that its velocity vector at time t is given by →V=a^i+(b−ct)^j. Its range on the horizontal plane is given by
Answer» A particle is projected from a horizontal plane (x-y plane) such that its velocity vector at time $t$ is given by $\to V = a^i + (b - c t)^j$ . Its range on the horizontal plane is given by

Discussion

33.	The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is
Answer» The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

33.

The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

Answer»

The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

Discussion

34.	The maximum speed that can be achieved without skidding by a car on a circular unbanked road of radius R and coefficient of static friction μ, is
Answer» The maximum speed that can be achieved without skidding by a car on a circular unbanked road of radius R and coefficient of static friction $μ$ , is

Discussion

35.	A point source of electromagnetic radiation has an average power output of 800W. The maximum value of electric field at a distance 3.5m from the source will be
Answer» A point source of electromagnetic radiation has an average power output of 800W. The maximum value of electric field at a distance 3.5m from the source will be

Discussion

36.	A set of 'n' identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is L. The block at one end is given a speed 'v' towards the next one at time, t = 0. All collisions are completely inelastic, then
Answer» A set of 'n' identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is L. The block at one end is given a speed 'v' towards the next one at time, t = 0. All collisions are completely inelastic, then

Discussion

37.	A light is at the top of a tower of height 47 meter. A man of height 2 meter, who is 90 meter away horizontally from the foot of the tower starts running with velocity 15m/sec towards the foot of the tower. At the same instant a ball which is placed in the same vertical plane of tower and man, dropped from the same height of the tower, 5meter horizontally away from the light on the side of the tower where man is placed. Assuming that ball falls according to the law S=5 t2 Answer the following The speed of the shadow (in m/sec) of ball moving along the ground at the instant t = 2 seconds is
Answer» A light is at the top of a tower of height 47 meter. A man of height 2 meter, who is 90 meter away horizontally from the foot of the tower starts running with velocity 15m/sec towards the foot of the tower. At the same instant a ball which is placed in the same vertical plane of tower and man, dropped from the same height of the tower, 5meter horizontally away from the light on the side of the tower where man is placed. Assuming that ball falls according to the law $S = 5 t^{2}$ Answer the following The speed of the shadow (in m/sec) of ball moving along the ground at the instant t = 2 seconds is

Discussion

38.	The temperature of 5 moles of a gas is changed from 100∘C to 120∘C at a constant volume. The change in internal energy is 80 J. Find the heat capacity of the gas at constant volume.
Answer» The temperature of 5 moles of a gas is changed from $100^{\circ} C$ to $120^{\circ} C$ at a constant volume. The change in internal energy is 80 J. Find the heat capacity of the gas at constant volume.

Discussion

39.	A block of mass 4 kg is placed on a rough horizontal plane. A time depedent force F=kt2 acts on the block, where k=2 N/s2. Coefficient of static friction μ=0.8. Force of friction between the block and the plane at t=2 s is
Answer» A block of mass $4 kg$ is placed on a rough horizontal plane. A time depedent force $F = k t^{2}$ acts on the block, where $k = 2 {N/s}^{2}$ . Coefficient of static friction $μ = 0.8$ . Force of friction between the block and the plane at $t = 2 s$ is

Discussion

40.	Two particles of mass m each are tied at the ends of a light string of length 2a. The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance ‘a’ from the center P(as shown in the figure). Now, the mid–point of the string is pulled vertically upwards with a small but constant force F. As a result, the particles move towards each other on the surface. The magnitude of acceleration, when the separation between them becomes 2x, is
Answer» Two particles of mass m each are tied at the ends of a light string of length 2a. The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance ‘a’ from the center P(as shown in the figure). Now, the mid–point of the string is pulled vertically upwards with a small but constant force F. As a result, the particles move towards each other on the surface. The magnitude of acceleration, when the separation between them becomes 2x, is

Discussion

41.	The earth (mass=6×1024kg) revolves around the sun with angular velocity 2×10−7rad/s in a circular orbit of radius 1.5×108 km. The force exerted by the sun on the earth in newtons is
Answer» The earth $(m a s s = 6 \times 10^{24} k g)$ revolves around the sun with angular velocity $2 \times 10^{- 7} r a d / s$ in a circular orbit of radius $1.5 \times 10^{8} k m$ . The force exerted by the sun on the earth in newtons is

Discussion

42.	A balloon filled with hydrogen has a volume of 1 m3 and its mass is 1 kg.The volume of the block of a very light material which it can just lift is [Density of material of block is 91.3 kg/m3 and that of air is 1.3 kg/m3]
Answer» A balloon filled with hydrogen has a volume of 1 $m^{3}$ and its mass is 1 kg.The volume of the block of a very light material which it can just lift is [Density of material of block is 91.3 kg/ $m^{3}$ and that of air is 1.3 kg/ $m^{3}$ ]

42.

A balloon filled with hydrogen has a volume of 1 m3 and its mass is 1 kg.The volume of the block of a very light material which it can just lift is [Density of material of block is 91.3 kg/m3 and that of air is 1.3 kg/m3]

Answer»

A balloon filled with hydrogen has a volume of 1 $m^{3}$ and its mass is 1 kg.The volume of the block of a very light material which it can just lift is

[Density of material of block is 91.3 kg/ $m^{3}$ and that of air is 1.3 kg/ $m^{3}$ ]

Discussion

43.	When a potential difference of 2V is applied across a resistor, you observed a current I. When the length of the resistor is doubled without changing the thickness, what is the current observed when 2V is applied across it.
Answer» When a potential difference of 2V is applied across a resistor, you observed a current I. When the length of the resistor is doubled without changing the thickness, what is the current observed when 2V is applied across it.

Discussion

44.	A uniform magnetic field B exists in the region between x=0 and x=3R2 (region 2 in the figure) pointing normally into the plane of the paper. A particle with charge +Q and momentum p directed along x-axis enters region 2 from region 1 at point P1(y=−R). Which of the following option(s) is/are correct?
Answer» A uniform magnetic field B exists in the region between $x = 0$ and $x = \frac{3 R}{2}$ (region 2 in the figure) pointing normally into the plane of the paper. A particle with charge $+ Q$ and momentum $p$ directed along x-axis enters region 2 from region 1 at point $P_{1} (y = - R)$ . Which of the following option(s) is/are correct?

Discussion

45.	The energy of a gas/litre is 300 joules, then its pressure will be
Answer» The energy of a gas/litre is 300 joules, then its pressure will be

Discussion

46.	Fresh water issues from the nozzle with a velocity of 20 m/sec at the rate of 0.03 m3/sec and is split into two equal streams by the fixed vane and deflected through 60∘ as shown in figure. The force in newtons required to hold the vane in place is (Assume area of cross section of water in each stream in A)
Answer» Fresh water issues from the nozzle with a velocity of $20 m / s e c$ at the rate of $0.03 m^{3} / s e c$ and is split into two equal streams by the fixed vane and deflected through $60^{\circ}$ as shown in figure. The force in newtons required to hold the vane in place is (Assume area of cross section of water in each stream in $A$ )

Discussion

47.	If D,E are the midpoints of AB, AC of ΔABC, then −−→BE+−−→DC
Answer» If D,E are the midpoints of AB, AC of $Δ A B C$ , then $- - \to B E + - - \to D C$

Discussion

48.	A particle moves along a parabolic path y=9x2 in such way that the x−component of velocity remains constant and has a value 13 m/s. The magnitude of acceleration of the particle is
Answer» A particle moves along a parabolic path $y = 9 x^{2}$ in such way that the $x -$ component of velocity remains constant and has a value $\frac{1}{3} m / s$ . The magnitude of acceleration of the particle is

Discussion

49.	A U shape tube contain fluid upto length l in both limbs as shown in figure. What would be the minimum angular velocity with which tube should be rotated about any of the limbs so that length of fluid in that limb reduces to zero?
Answer» A U shape tube contain fluid upto length $l$ in both limbs as shown in figure. What would be the minimum angular velocity with which tube should be rotated about any of the limbs so that length of fluid in that limb reduces to zero?

Discussion

50.	A bead B of mass ‘m’ can travel without friction on a smooth horizontal wire xx’. The bead is connected to a block of identical mass by an ideal string passing over an ideal pulley. The system, as shown, is in vertical plane. The system is allowed to fall. Find the speed of block A at the instant when string connected to the bead B makes an angle 37∘ with vertical.
Answer» A bead B of mass ‘m’ can travel without friction on a smooth horizontal wire xx’. The bead is connected to a block of identical mass by an ideal string passing over an ideal pulley. The system, as shown, is in vertical plane. The system is allowed to fall. Find the speed of block A at the instant when string connected to the bead B makes an angle $37^{\circ}$ with vertical.

50.

A bead B of mass ‘m’ can travel without friction on a smooth horizontal wire xx’. The bead is connected to a block of identical mass by an ideal string passing over an ideal pulley. The system, as shown, is in vertical plane. The system is allowed to fall. Find the speed of block A at the instant when string connected to the bead B makes an angle 37∘ with vertical.

Answer»

A bead B of mass ‘m’ can travel without friction on a smooth horizontal wire xx’. The bead is connected to a block of identical mass by an ideal string passing over an ideal pulley. The system, as shown, is in vertical plane.

The system is allowed to fall. Find the speed of block A at the instant when string connected to the bead B makes an angle $37^{\circ}$ with vertical.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A smooth piston of mass m and area of cross-section A is in equilibrium with the gas in the jar, when the pressure of the gas is P0. Find the angular frequency of oscillation of the piston, assuming adiabatic change of state of the gas.

A smooth ring of mass can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley and carries a block C of mass as shown below. As the ring starts sliding.

A ball is dropped from a height. If the maximum percentage errors in measurement of the height and the time are e1 and e2 respectively, then maximum percentage error in the estimation of g is

Velocity of the boat with respect to river (vb/r) is 10 m/s. It passes the river of width 36 m and reaches opposite shore at point R shown in the figure. If the velocity of the river is 3 m/s, find the time of the trip and drift of the boat.

A force f(bar)=5i(cap)–3j(cap)+2k(cap) moves a particle from r1(bar)=2i+7j+4k to r2=5i+2j+8k. Calculate the work done

The old gramophone record player spins the disc at a constant frequency of 75 Hz. Find the average angular velocity of the disk.

Velocity-time graph of an object is given below. The corresponding displacement – time graph is:

A galvanometer of resistance 80 ohm, shunted by a resistance of 20 ohm is joined in series with a resistance of 200 ohm and cell of emf 1.5V What is the sensitivity of the galvanometer if it shows a deflection of 30 divisions.

Fluid used in the column is mercury. The pressure of the gas in the cylinder is : Given : Atmospheric pressure =1.01×105 N/m2, g=10 m/s2 and density of mercury =13600 kg/m3.

What is the voltage gain in a common emitter, where input resistance is 3Ω and the load resistance is 24Ω, β = 0.6

Water rises in a vertical capillary tube up to 2√2 cm. If the tube is inclined at an angle θ∘, the length of water risen in the tube is 4 cm. Find the value of θ.

How do we know that when do we have to use dot product and cross product in a problem?

Λ of a M32 solution of a weak acid is 8 S cm2 mol−1 and the limiting molar conductivity is 400 S cm2 mol−1. Ka of the acid is:

The values of L and R in LCR circuit are 1 mH and 10 Ω respectively. What is the value of its bandwidth?

A vessel contains oil (density 0.8 g/cm2) over mercury (density 13.6 g/cm3). A homogeneous sphere floats with half its volume immersed in mercury and the other half in oil. The density of the material of the sphere in g/cm3 is

Which out of electron and photon possess more energy for a given frequency? Can students contact on Monday?

When a system absorbs heat,the molecules start moving faster because kinetic energy increases,hence disorder increases. For the same amount of heat absorbed at lower temperature,the disorder is more than at higher temperature.why?explain.

A truck is moving with a constant velocity of 54 km/h. In which direction (angle with the direction of motion of truck) should a stone be projected up with a velocity of 20 m/s relative to truck, so that for a person standing on the earth stone appears to be at right angles to the truck ?

A spring is cut in two halves. The spring constant of each half becomes

Find the average force needed to accelerate a car weighing 500 kg from rest to 72 km/h in a distance of 25 m.

In an atom, an electron is moving with the speed of 660 m/s have an accuracy of 0.005%. The minimum uncertainty with which the position of the electron can be located is: (h=6.6×10−34 J s;mass of electron,em=9×10−31 kg and π=3)

What is the gravitational pull between two electrons?

Each condenser in the figure shown has a capacity of 3 μF. The equivalent capacity between the terminals A and B is

The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit. The current IZ through the Zener is

Find the number of photons emitted per second by a 24 W source of monochromatic light of wavelength 6600 ∘A :

A disc of mass m and radius R is resting on horizontal surface with coefficient of friction μ. If sudden velocity V0 (without any angular velocity) is imparted to disc then time after which disc starts pure rolling is

A particle is projected from a horizontal plane (x-y plane) such that its velocity vector at time t is given by →V=a^i+(b−ct)^j. Its range on the horizontal plane is given by

The maximum speed that can be achieved without skidding by a car on a circular unbanked road of radius R and coefficient of static friction μ, is

A point source of electromagnetic radiation has an average power output of 800W. The maximum value of electric field at a distance 3.5m from the source will be

The temperature of 5 moles of a gas is changed from 100∘C to 120∘C at a constant volume. The change in internal energy is 80 J. Find the heat capacity of the gas at constant volume.

A block of mass 4 kg is placed on a rough horizontal plane. A time depedent force F=kt2 acts on the block, where k=2 N/s2. Coefficient of static friction μ=0.8. Force of friction between the block and the plane at t=2 s is

The earth (mass=6×1024kg) revolves around the sun with angular velocity 2×10−7rad/s in a circular orbit of radius 1.5×108 km. The force exerted by the sun on the earth in newtons is

A balloon filled with hydrogen has a volume of 1 m3 and its mass is 1 kg.The volume of the block of a very light material which it can just lift is [Density of material of block is 91.3 kg/m3 and that of air is 1.3 kg/m3]

When a potential difference of 2V is applied across a resistor, you observed a current I. When the length of the resistor is doubled without changing the thickness, what is the current observed when 2V is applied across it.

The energy of a gas/litre is 300 joules, then its pressure will be

If D,E are the midpoints of AB, AC of ΔABC, then −−→BE+−−→DC

A particle moves along a parabolic path y=9x2 in such way that the x−component of velocity remains constant and has a value 13 m/s. The magnitude of acceleration of the particle is

A U shape tube contain fluid upto length l in both limbs as shown in figure. What would be the minimum angular velocity with which tube should be rotated about any of the limbs so that length of fluid in that limb reduces to zero?