50278 + Interview Questions in Physics

1.	An infinite number of charges, each equal to 4C, are placed along the x-axis at x = 1 m, x = 2 m, x = 4 m, x = 8 m and so on. The total force on a charge of 1C placed at the origin is
Answer» An infinite number of charges, each equal to 4C, are placed along the x-axis at x = 1 m, x = 2 m, x = 4 m, x = 8 m and so on. The total force on a charge of 1C placed at the origin is

1.

An infinite number of charges, each equal to 4C, are placed along the x-axis at x = 1 m, x = 2 m, x = 4 m, x = 8 m and so on. The total force on a charge of 1C placed at the origin is

Answer»

An infinite number of charges, each equal to 4C, are placed along the x-axis at x = 1 m, x = 2 m, x = 4 m, x = 8 m and so on. The total force on a charge of 1C placed at the origin is

Discussion

2.	We have E=mc². Generally kinetic energy of anything is ½mv². So shudnt it be E=½mc² instead of just mc²?? Where.. m is mass and and c is the velocity??🤔
Answer» We have E=mc². Generally kinetic energy of anything is ½mv². So shudnt it be E=½mc² instead of just mc²?? Where.. m is mass and and c is the velocity??🤔

2.

We have E=mc². Generally kinetic energy of anything is ½mv². So shudnt it be E=½mc² instead of just mc²?? Where.. m is mass and and c is the velocity??🤔

Answer»

We have E=mc².

Generally kinetic energy of anything is ½mv².

So shudnt it be E=½mc² instead of just mc²?? Where.. m is mass and and c is the velocity??🤔

Discussion

3.	Two cylindrical rods of lengths l1 and l2, radii r1 and r2 have thermal conductivities k1 and k2 respectively. The ends of the rods are maintained at the same temperature difference. If l1=2l2 and r1=r22, the rates of heat flow in them will be the same if k1k2 is
Answer» Two cylindrical rods of lengths $l_{1} a n d l_{2}$ , radii $r_{1} a n d r_{2}$ have thermal conductivities $k_{1} a n d k_{2}$ respectively. The ends of the rods are maintained at the same temperature difference. If $l_{1} = 2 l_{2} a n d r_{1} = \frac{r_{2}}{2}$ , the rates of heat flow in them will be the same if $\frac{k_{1}}{k_{2}}$ is

Discussion

4.	Figure 3.21 shows the x-t plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t < 0 and on a parabolic path for t > 0? If not, suggest a suitable physical context for this graph.
Answer» Figure 3.21 shows the x-t plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t < 0 and on a parabolic path for t > 0? If not, suggest a suitable physical context for this graph.

Discussion

5.	All the things are made up of atoms . atom has the electrons in the outer having negative charge, then why no repulsing force is produced when two things are comes to contact with each other.
Answer» All the things are made up of atoms . atom has the electrons in the outer having negative charge, then why no repulsing force is produced when two things are comes to contact with each other.

Discussion

6.	A car is moving in a rainstorm at a speed of 36 km/hr. The rain drops fall vertically w.r.t the ground with a constant speed of 20 m/s. The speed of the raindrops w.r.t the car is
Answer» A car is moving in a rainstorm at a speed of $36 km/hr$ . The rain drops fall vertically w.r.t the ground with a constant speed of $20 m/s$ . The speed of the raindrops w.r.t the car is

Discussion

7.	A small block is shot into each of the four tracks as shown in the options. Each of the tracks rises to the same height. The speed with which the block enters the track is the same in all cases. At the highest point of the track, the normal reaction is maximum in -
Answer» A small block is shot into each of the four tracks as shown in the options. Each of the tracks rises to the same height. The speed with which the block enters the track is the same in all cases. At the highest point of the track, the normal reaction is maximum in -

Discussion

8.	A thin uniform cylindrical shell, closed at both ends, is partially filled with water. It is floating vertically in water in half – submerged state. If ρc is the relative density of the material of the shell with respect to water, then the correct statement is that the shell is
Answer» A thin uniform cylindrical shell, closed at both ends, is partially filled with water. It is floating vertically in water in half – submerged state. If $ρ_{c}$ is the relative density of the material of the shell with respect to water, then the correct statement is that the shell is

Discussion

9.	A Man moves on a straight horizontal road with a block of 2kg in his hand. If he covers a distance of 20m with constant velocity of 1m/s. Find work done by man on block during motion.
Answer» A Man moves on a straight horizontal road with a block of 2kg in his hand. If he covers a distance of 20m with constant velocity of 1m/s. Find work done by man on block during motion.

Discussion

10.	What would happen to a dipole when it is released from a state of unstable equilibrium ?In Which orientation will get aligned to ?
Answer» What would happen to a dipole when it is released from a state of unstable equilibrium ?In Which orientation will get aligned to ?

Discussion

11.	Three constant forces −→F1=(2^i−3^j+2^k) N,−→F2=(^i+^j−^k) N and −→F3=(3^i+^j−2^k) N displace a particle from (1,−1,2) m to (−1,−1,3) m and then to (2,3,4) m, displacement being measured in meters. Find the total work done by the forces.
Answer» Three constant forces $_{1} = (2^i - 3^j + 2^k) N,_{2} = (^i +^j -^k) N$ and $_{3} = (3^i +^j - 2^k) N$ displace a particle from $(1, - 1, 2) m$ to $(- 1, - 1, 3) m$ and then to $(2, 3, 4) m$ , displacement being measured in meters. Find the total work done by the forces.

Discussion

12.	Calculate the focal length of the thin lens shown in figure. The points C1 and C2 denote the centres of curvature. Refractive index of lens is 1.5.
Answer» Calculate the focal length of the thin lens shown in figure. The points $C_{1}$ and $C_{2}$ denote the centres of curvature. Refractive index of lens is $1.5$ .

12.

Calculate the focal length of the thin lens shown in figure. The points C1 and C2 denote the centres of curvature. Refractive index of lens is 1.5.

Answer»

Calculate the focal length of the thin lens shown in figure. The points $C_{1}$ and $C_{2}$ denote the centres of curvature. Refractive index of lens is $1.5$ .

Discussion

13.	Find the MOI of a uniform circular disc of mass M=10 kg and radius R=10 m about tangent perpendicular to its plane.
Answer» Find the MOI of a uniform circular disc of mass $M = 10 kg$ and radius $R = 10 m$ about tangent perpendicular to its plane.

Discussion

14.	A soap bubble of radius r is blown up to form a bubble of radius 2r under isothermal conditions. If σ is the surface tension of soap solution, the energy spent in doing so is
Answer» A soap bubble of radius r is blown up to form a bubble of radius 2r under isothermal conditions. If $σ$ is the surface tension of soap solution, the energy spent in doing so is

Discussion

15.	A large horizontal surface moves up and down in SHM with an amplitude of 1 cm. If a mass of 10 kg (which is placed on the surface) is to remain continually in contact with it, the maximum frequency of S.H.M. will be
Answer» A large horizontal surface moves up and down in SHM with an amplitude of 1 cm. If a mass of 10 kg (which is placed on the surface) is to remain continually in contact with it, the maximum frequency of S.H.M. will be

15.

A large horizontal surface moves up and down in SHM with an amplitude of 1 cm. If a mass of 10 kg (which is placed on the surface) is to remain continually in contact with it, the maximum frequency of S.H.M. will be

Answer»

A large horizontal surface moves up and down in SHM with an amplitude of 1 cm. If a mass of 10 kg (which is placed on the surface) is to remain continually in contact with it, the maximum frequency of S.H.M. will be

Discussion

16.	A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are αC and (\alpha_B\) . On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Then R is
Answer» A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are $α_{C}$ and (\alpha_B\). On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Then R is

16.

A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are αC and (\alpha_B\) . On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Then R is

Answer»

A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are $α_{C}$ and (\alpha_B\). On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Then R is

Discussion

17.	In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001;AFMC 2002; CPMT 2004]
Answer» In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001;AFMC 2002; CPMT 2004]

17.

In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001;AFMC 2002; CPMT 2004]

Answer»

In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is

[CBSE PMT 1998; AIIMS 2001;AFMC 2002; CPMT 2004]

Discussion

18.	A glass plate 0.6 micron thickness is illuminated by a beam of white light of wavelength λ normal to the plane. λ is in the range of 400 nm and 750 nm. Refractive index of glass is 1.5. Wavelengths that get intensified in the reflected beam are
Answer» A glass plate 0.6 micron thickness is illuminated by a beam of white light of wavelength $λ$ normal to the plane. $λ$ is in the range of 400 $n m$ and 750 $n m$ . Refractive index of glass is 1.5. Wavelengths that get intensified in the reflected beam are

Discussion

19.	A shell acquires the initial velocity v = 320 m/s, having made n = 2.0 turns inside the barrel whose length is equal to l = 2.0 m. Assuming that the shell moves inside the barrel with a uniform acceleration, find the angular velocity of its axial rotation at the moment when the shell escapes the barrel.
Answer» A shell acquires the initial velocity $v$ = 320 m/s, having made $n$ = 2.0 turns inside the barrel whose length is equal to $l$ = 2.0 m. Assuming that the shell moves inside the barrel with a uniform acceleration, find the angular velocity of its axial rotation at the moment when the shell escapes the barrel.

Discussion

20.	An object is displaced from point A(1,0) m to a point B(0,4) m under the influence of a force →F=−2^i+5^j. The workdone by this force is
Answer» An object is displaced from point $A (1, 0) m$ to a point $B (0, 4) m$ under the influence of a force $\to F = - 2^i + 5^j .$ The workdone by this force is

Discussion

21.	Three charges are arranged on the vertices of an equilateral triangle as shown in figurre (29-E6). Find the eipole moment of the combination.
Answer» Three charges are arranged on the vertices of an equilateral triangle as shown in figurre (29-E6). Find the eipole moment of the combination.

Discussion

22.	Voltmeter is a device that measures
Answer» Voltmeter is a device that measures

Discussion

23.	P wave represents:
Answer» P wave represents:

Discussion

24.	In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 43, without disturbing the geometrical arrangement, what is the new fringe width?
Answer» In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index $\frac{4}{3}$ , without disturbing the geometrical arrangement, what is the new fringe width?

Discussion

25.	What is the dimension of (½)at2?
Answer» What is the dimension of (½)at²?

Discussion

26.	The power of a motor is 40 kW, the speed at which it can raise a load of 20,000 N is
Answer» The power of a motor is 40 kW, the speed at which it can raise a load of 20,000 N is

Discussion

27.	A body of mass m accelerates uniformly from rest to v1 in time t1. As a function of time t, the instantaneous power delivered to the body is [2004 AIEEE]
Answer» A body of mass $m$ accelerates uniformly from rest to $v_{1}$ in time $t_{1}$ . As a function of time $t$ , the instantaneous power delivered to the body is [2004 AIEEE]

Discussion

28.	A tree stands vertically on a hill side which makes an angle of 15∘with the horizontal. From a point on the ground 35 m down the hill from the base of tree, the angle of elevation of the top of tree is 60∘. Find the height of the tree.
Answer» A tree stands vertically on a hill side which makes an angle of $15^{\circ}$ with the horizontal. From a point on the ground 35 m down the hill from the base of tree, the angle of elevation of the top of tree is $60^{\circ}$ . Find the height of the tree.

Discussion

29.	The density ρ of a liquid varies with depth h from the free surface as ρ=kh. A small body of density ρ1 is released from the surface of the liquid. The body executes SHM with amplitude
Answer» The density $ρ$ of a liquid varies with depth $h$ from the free surface as $ρ = k h$ . A small body of density $ρ_{1}$ is released from the surface of the liquid. The body executes $S H M$ with amplitude

Discussion

30.	If f(x)=√xg(x), where g(4)=2 and g′(4)=3, find f′(4).
Answer» If $f (x) = \sqrt{x} g (x)$ , where $g (4) = 2$ and $g^{'} (4) = 3$ , find $f^{'} (4)$ .

Discussion

31.	Two identical parallel plate capacitors of capacitance C each are connected in series with a battery of Emf, E as shown. If one of the capacitors is now filled with dielectric constant k, the amount of charge which will flow through the battery is
Answer» Two identical parallel plate capacitors of capacitance C each are connected in series with a battery of Emf, E as shown. If one of the capacitors is now filled with dielectric constant k, the amount of charge which will flow through the battery is

Discussion

32.	Let n droplets each of radius r coalesce to form a large drop of radius R. Assuming that the droplets are incompressible and S is the surface tension. Calculate the rise in temperature, if C is the specific heat and ρ is the density.
Answer» Let $n$ droplets each of radius $r$ coalesce to form a large drop of radius $R$ . Assuming that the droplets are incompressible and $S$ is the surface tension. Calculate the rise in temperature, if $C$ is the specific heat and $ρ$ is the density.

Discussion

33.	A 2 kg mass moving with a velocity of 10 ms−1 collides with another 6 kg mass moving in opposite direction with a velocity of 20 ms−1. After the collision, they stick and move together. Find their common velocity and the momentum.
Answer» A 2 kg mass moving with a velocity of $10 m s^{- 1}$ collides with another 6 kg mass moving in opposite direction with a velocity of $20 m s^{- 1}$ . After the collision, they stick and move together. Find their common velocity and the momentum.

Discussion

34.	Two resistances R1 and R2 provide series to parallel equivalents as n1. Then the correct relationship is
Answer» Two resistances $R_{1}$ and $R_{2}$ provide series to parallel equivalents as $\frac{n}{1}$ . Then the correct relationship is

Discussion

35.	A mercury drop of radius 1 cm is sprayed into 106 droplets of equal size. Calculate the energy expended ( in mJ upto two decimals) if surface tension of mercury is 35×10−3 N/m.
Answer» A mercury drop of radius $1 cm$ is sprayed into $10^{6}$ droplets of equal size. Calculate the energy expended ( in $mJ$ upto two decimals) if surface tension of mercury is $35 \times 10^{- 3} N/m$ .

Discussion

36.	Calculate the force required to lift a load of 60 N, placed at a distance of 3 m from the fulcrum, if the effort is applied at a distance of 6 cm from the fulcrum.
Answer» Calculate the force required to lift a load of $60 N$ , placed at a distance of $3 m$ from the fulcrum, if the effort is applied at a distance of $6 cm$ from the fulcrum.

Discussion

37.	When a horse pulls a cart, the force that helps the cart move forward is the force exerted by :
Answer» When a horse pulls a cart, the force that helps the cart move forward is the force exerted by :

Discussion

38.	Find the ratio of the linear momenta of two particles of masses 1.0 kg and 4.0 kg if their kinetic energies are equal.
Answer» Find the ratio of the linear momenta of two particles of masses 1.0 kg and 4.0 kg if their kinetic energies are equal.

Discussion

39.	A coil having n turns and resistance R Ω is connected with a galvanometer of resistance 4RΩ . This combination is moved in time t seconds from a magnetic field W1 weber to W2 weber. The induced current in the circuit is
Answer» A coil having n turns and resistance R $Ω$ is connected with a galvanometer of resistance 4R $Ω$ . This combination is moved in time t seconds from a magnetic field $W_{1}$ weber to $W_{2}$ weber. The induced current in the circuit is

Discussion

40.	A driver takes 0.20 s to apply the brake after he sees a need for it. This is called the reaction time of the driver. If he is driving a car at a speed of 54 km/h and the brakes cause a deceleration of 6 m/s2 find the distance traveled by car after he sees the need to put the brakes on.
Answer» A driver takes 0.20 s to apply the brake after he sees a need for it. This is called the reaction time of the driver. If he is driving a car at a speed of 54 km/h and the brakes cause a deceleration of 6 m/ $s^{2}$ find the distance traveled by car after he sees the need to put the brakes on.

Discussion

41.	Among (i) temperature and (ii) mass which is an intensive property?
Answer» Among (i) temperature and (ii) mass which is an intensive property?

Discussion

42.	In a beryllium atom, if a0be the radius of the first orbit, then the radius of the second orbit will be in general
Answer» In a beryllium atom, if $a_{0}$ be the radius of the first orbit, then the radius of the second orbit will be in general

Discussion

43.	Two masses m and 2m are suspended together by a massless spring of force constant K. When the masses are in equilibrium, mass m is removed without disturbing the system. Then, the amplitude of vibration of the system is:
Answer» Two masses $m$ and $2 m$ are suspended together by a massless spring of force constant $K$ . When the masses are in equilibrium, mass $m$ is removed without disturbing the system. Then, the amplitude of vibration of the system is:

Discussion

44.	The magnetic induction at a point P which is distant 4 cm from a long current carrying wire is 10−3 Telsa.The field of induction at a distance 12 cm from the same current would be
Answer» The magnetic induction at a point P which is distant 4 cm from a long current carrying wire is $10^{- 3}$ Telsa.The field of induction at a distance 12 cm from the same current would be

Discussion

45.	If →r.^i=→r.^j=→r.^k and \|r\|=3, then find →r.
Answer» If $\to r .^i = \to r .^j = \to r .^k$ and $\| r \| = 3$ , then find $\to r$ .

Discussion

46.	Four springs are attached to a mass m as shown. The time period will be 2π times:
Answer» Four springs are attached to a mass m as shown. The time period will be $2 π$ times:

Discussion

47.	The coefficient of friction between the block and the surface is 0.4 in Fig. (i-iv). Match Column I with Column II. Column IColumn IIi. Force of friction is zero ina. Fig. (i)ii. Force of friction is 2.5 N inb. Fig. (ii)iii. Acceleration of the block is zero inc. Fig. (iiii)iv. Normal force is not equal to 2g in d. Fig. (iv)
Answer» The coefficient of friction between the block and the surface is $0.4$ in Fig. (i-iv). Match Column I with Column II. $\begin{matrix} Column I & Column II i. Force of friction is zero in & a. Fig. (i) ii. Force of friction is 2.5 N in & b. Fig. (ii) iii. Acceleration of the block is zero in & c. Fig. (iiii) iv. Normal force is not equal to 2 g in & d. Fig. (iv) \end{matrix}$

Discussion

48.	A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same rate of heat conduction and the same temperature drop, this can be replaced by a diatomite wall of conductivity 0.14 W/mK and the same cross-sectional area. Find the thickness of the diatomite wall.
Answer» A furnace is made of a red brick wall of thickness $0.5 m$ and conductivity $0.7 W/mK$ . For the same rate of heat conduction and the same temperature drop, this can be replaced by a diatomite wall of conductivity $0.14 W/mK$ and the same cross-sectional area. Find the thickness of the diatomite wall.

Discussion

49.	A box P and a coil Q are connected in series with an ac source of variable frequency. The emf of the source is constant at 10 V. Box P contains a capacitance of 1 μF in series with a resistance of 32 Ω. Coil Q has a self inductance of 4.9 mH and a resistance of 68 Ω in series. The frequency is adjusted so that maximum current flows in P and Q. The voltage across Q is
Answer» A box P and a coil Q are connected in series with an ac source of variable frequency. The emf of the source is constant at $10 V$ . Box P contains a capacitance of $1 μ F$ in series with a resistance of $32 Ω$ . Coil Q has a self inductance of 4.9 mH and a resistance of $68 Ω$ in series. The frequency is adjusted so that maximum current flows in P and Q. The voltage across Q is

Discussion

50.	Which element has the greatest tendency to lose electrons.
Answer» Which element has the greatest tendency to lose electrons.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

An infinite number of charges, each equal to 4C, are placed along the x-axis at x = 1 m, x = 2 m, x = 4 m, x = 8 m and so on. The total force on a charge of 1C placed at the origin is

We have E=mc². Generally kinetic energy of anything is ½mv². So shudnt it be E=½mc² instead of just mc²?? Where.. m is mass and and c is the velocity??🤔

Two cylindrical rods of lengths l1 and l2, radii r1 and r2 have thermal conductivities k1 and k2 respectively. The ends of the rods are maintained at the same temperature difference. If l1=2l2 and r1=r22, the rates of heat flow in them will be the same if k1k2 is

Figure 3.21 shows the x-t plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t &lt; 0 and on a parabolic path for t &gt; 0? If not, suggest a suitable physical context for this graph.

All the things are made up of atoms . atom has the electrons in the outer having negative charge, then why no repulsing force is produced when two things are comes to contact with each other.

A car is moving in a rainstorm at a speed of 36 km/hr. The rain drops fall vertically w.r.t the ground with a constant speed of 20 m/s. The speed of the raindrops w.r.t the car is

A small block is shot into each of the four tracks as shown in the options. Each of the tracks rises to the same height. The speed with which the block enters the track is the same in all cases. At the highest point of the track, the normal reaction is maximum in -

A thin uniform cylindrical shell, closed at both ends, is partially filled with water. It is floating vertically in water in half – submerged state. If ρc is the relative density of the material of the shell with respect to water, then the correct statement is that the shell is

A Man moves on a straight horizontal road with a block of 2kg in his hand. If he covers a distance of 20m with constant velocity of 1m/s. Find work done by man on block during motion.

What would happen to a dipole when it is released from a state of unstable equilibrium ?In Which orientation will get aligned to ?

Three constant forces −→F1=(2^i−3^j+2^k) N,−→F2=(^i+^j−^k) N and −→F3=(3^i+^j−2^k) N displace a particle from (1,−1,2) m to (−1,−1,3) m and then to (2,3,4) m, displacement being measured in meters. Find the total work done by the forces.

Calculate the focal length of the thin lens shown in figure. The points C1 and C2 denote the centres of curvature. Refractive index of lens is 1.5.

Find the MOI of a uniform circular disc of mass M=10 kg and radius R=10 m about tangent perpendicular to its plane.

A soap bubble of radius r is blown up to form a bubble of radius 2r under isothermal conditions. If σ is the surface tension of soap solution, the energy spent in doing so is

A large horizontal surface moves up and down in SHM with an amplitude of 1 cm. If a mass of 10 kg (which is placed on the surface) is to remain continually in contact with it, the maximum frequency of S.H.M. will be

A bimetallic strip is formed out of two identical strips, one of copper and other of brass. The coefficients of linear expansion of the two metals are αC and (\alpha_B\) . On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Then R is

In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001;AFMC 2002; CPMT 2004]

A glass plate 0.6 micron thickness is illuminated by a beam of white light of wavelength λ normal to the plane. λ is in the range of 400 nm and 750 nm. Refractive index of glass is 1.5. Wavelengths that get intensified in the reflected beam are

An object is displaced from point A(1,0) m to a point B(0,4) m under the influence of a force →F=−2^i+5^j. The workdone by this force is

Three charges are arranged on the vertices of an equilateral triangle as shown in figurre (29-E6). Find the eipole moment of the combination.

Voltmeter is a device that measures

P wave represents:

In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index 43, without disturbing the geometrical arrangement, what is the new fringe width?

What is the dimension of (½)at2?

The power of a motor is 40 kW, the speed at which it can raise a load of 20,000 N is

A body of mass m accelerates uniformly from rest to v1 in time t1. As a function of time t, the instantaneous power delivered to the body is [2004 AIEEE]

A tree stands vertically on a hill side which makes an angle of 15∘with the horizontal. From a point on the ground 35 m down the hill from the base of tree, the angle of elevation of the top of tree is 60∘. Find the height of the tree.

The density ρ of a liquid varies with depth h from the free surface as ρ=kh. A small body of density ρ1 is released from the surface of the liquid. The body executes SHM with amplitude

If f(x)=√xg(x), where g(4)=2 and g′(4)=3, find f′(4).

Two identical parallel plate capacitors of capacitance C each are connected in series with a battery of Emf, E as shown. If one of the capacitors is now filled with dielectric constant k, the amount of charge which will flow through the battery is

Let n droplets each of radius r coalesce to form a large drop of radius R. Assuming that the droplets are incompressible and S is the surface tension. Calculate the rise in temperature, if C is the specific heat and ρ is the density.

A 2 kg mass moving with a velocity of 10 ms−1 collides with another 6 kg mass moving in opposite direction with a velocity of 20 ms−1. After the collision, they stick and move together. Find their common velocity and the momentum.

Two resistances R1 and R2 provide series to parallel equivalents as n1. Then the correct relationship is

A mercury drop of radius 1 cm is sprayed into 106 droplets of equal size. Calculate the energy expended ( in mJ upto two decimals) if surface tension of mercury is 35×10−3 N/m.

Calculate the force required to lift a load of 60 N, placed at a distance of 3 m from the fulcrum, if the effort is applied at a distance of 6 cm from the fulcrum.

When a horse pulls a cart, the force that helps the cart move forward is the force exerted by :

Find the ratio of the linear momenta of two particles of masses 1.0 kg and 4.0 kg if their kinetic energies are equal.

A coil having n turns and resistance R Ω is connected with a galvanometer of resistance 4RΩ . This combination is moved in time t seconds from a magnetic field W1 weber to W2 weber. The induced current in the circuit is

A driver takes 0.20 s to apply the brake after he sees a need for it. This is called the reaction time of the driver. If he is driving a car at a speed of 54 km/h and the brakes cause a deceleration of 6 m/s2 find the distance traveled by car after he sees the need to put the brakes on.

Among (i) temperature and (ii) mass which is an intensive property?

In a beryllium atom, if a0be the radius of the first orbit, then the radius of the second orbit will be in general

Two masses m and 2m are suspended together by a massless spring of force constant K. When the masses are in equilibrium, mass m is removed without disturbing the system. Then, the amplitude of vibration of the system is:

The magnetic induction at a point P which is distant 4 cm from a long current carrying wire is 10−3 Telsa.The field of induction at a distance 12 cm from the same current would be

If →r.^i=→r.^j=→r.^k and |r|=3, then find →r.

Four springs are attached to a mass m as shown. The time period will be 2π times:

A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same rate of heat conduction and the same temperature drop, this can be replaced by a diatomite wall of conductivity 0.14 W/mK and the same cross-sectional area. Find the thickness of the diatomite wall.

Which element has the greatest tendency to lose electrons.

Figure 3.21 shows the x-t plot of one-dimensional motion of a particle. Is it correct to say from the graph that the particle moves in a straight line for t < 0 and on a parabolic path for t > 0? If not, suggest a suitable physical context for this graph.