50278 + Interview Questions in Physics

1.	If photons have no mass, how can they have momentum?
Answer» If photons have no mass, how can they have momentum?

Discussion

2.	Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is 6.5×10–7 C? The radii of A and B are negligible compared to the distance of separation. What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?
Answer» Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is $6.5 \times 10^{- 7}$ C? The radii of A and B are negligible compared to the distance of separation. What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?

2.

Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is 6.5×10–7 C? The radii of A and B are negligible compared to the distance of separation. What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?

Answer»

Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is $6.5 \times 10^{- 7}$ C? The radii of A and B are negligible compared to the distance of separation.

What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?

Discussion

3.	Focal length of equiconvex lens with radius of each surface being 30 cm and refractive index 1.5, is
Answer» Focal length of equiconvex lens with radius of each surface being $30 c m$ and refractive index $1.5$ , is

Discussion

4.	The loudness and pitch of a sound depends on
Answer» The loudness and pitch of a sound depends on

4.

The loudness and pitch of a sound depends on

Answer»

The loudness and pitch of a sound depends on

Discussion

5.	A source of sound emitting a 1200 Hz note travels along a straight line at a speed of 170 m s−1. A detector is placed at a distance of 200 m from the line of motion of the source. (a) Find the frequency of sound received by the detector at the instant when the source gets closest to it. (b) Find the distance between the source and the detector at the instant it detects the frequency 1200 Hz. Velocity of sound in air =340 ms−1.
Answer» A source of sound emitting a 1200 Hz note travels along a straight line at a speed of $170 m s^{- 1}$ . A detector is placed at a distance of 200 m from the line of motion of the source. (a) Find the frequency of sound received by the detector at the instant when the source gets closest to it. (b) Find the distance between the source and the detector at the instant it detects the frequency 1200 Hz. Velocity of sound in air $= 340 m s^{- 1}$ .

Discussion

6.	A block is kept on a frictionless inclined surface with angle of inclination ′α′. The incline is given an acceleration 'a' to keep the block stationary. Then a is equal to
Answer» A block is kept on a frictionless inclined surface with angle of inclination $^{'} α^{'}$ . The incline is given an acceleration 'a' to keep the block stationary. Then a is equal to

Discussion

7.	V-u = distance travelled is correct or not .
Answer» V-u = distance travelled is correct or not .

Discussion

8.	Using figure (22.1), find the relative luminosity of wavelength (a) 480 nm, (b)520 nm (c) 580 nm and (d) 600 nm.
Answer» Using figure (22.1), find the relative luminosity of wavelength (a) 480 nm, (b)520 nm (c) 580 nm and (d) 600 nm.

Discussion

9.	If the capacitance of each capacitor is C, then effective capacitance of the shown network across any two junctions is
Answer» If the capacitance of each capacitor is C, then effective capacitance of the shown network across any two junctions is

Discussion

10.	Let ABCD be a trapezium with AD parallel to BC. Assume there is a point M in the interior of the segment BC such that AB = AM and DC = DM. Then the ratio of the area of the trapezium to the area of triangle AMD is.
Answer» Let ABCD be a trapezium with AD parallel to BC. Assume there is a point M in the interior of the segment BC such that AB = AM and DC = DM. Then the ratio of the area of the trapezium to the area of triangle AMD is.

Discussion

11.	The temperature of argon, kept in a vessel is raised by 1∘C at a constant volume. The total heat supplied to the gas is a combination of translational and rotational energies. Their respective shares are
Answer» The temperature of argon, kept in a vessel is raised by $1^{\circ} C$ at a constant volume. The total heat supplied to the gas is a combination of translational and rotational energies. Their respective shares are

Discussion

12.	The room heater can provide only 16∘C in the room when the temperature outside is −20∘C. It is not warm and comfortable, that is why the electric stove with power of 1 kW is also plugged in. Together these two devices maintain the room temperature of 22∘C. The thermal power of the heater (in kW) is
Answer» The room heater can provide only $16^{\circ} C$ in the room when the temperature outside is $- 20^{\circ} C$ . It is not warm and comfortable, that is why the electric stove with power of $1 kW$ is also plugged in. Together these two devices maintain the room temperature of $22^{\circ} C$ . The thermal power of the heater (in kW) is

Discussion

13.	Two particle A and B are moving with uniform velocity as shown in the figure given below at t =0. I. Will the two particle collide II. Find out shortest distance between two particles
Answer» Two particle A and B are moving with uniform velocity as shown in the figure given below at t =0. I. Will the two particle collide II. Find out shortest distance between two particles

Discussion

14.	What is the radius of curvature of a convex mirror if the focal length is 60 cm?
Answer» What is the radius of curvature of a convex mirror if the focal length is $60 cm$ ?

Discussion

15.	A body of mass 2 kg is projected with a speed 4 m/s at an angle 45∘ to the horizontal. What will be its angular momentum about the point of projection when the body is at the highest point in its trajectory?
Answer» A body of mass $2 kg$ is projected with a speed $4 m/s$ at an angle $45^{\circ}$ to the horizontal. What will be its angular momentum about the point of projection when the body is at the highest point in its trajectory?

Discussion

16.	Two conducting thin concentric shells of radii r and 3r is shown below. Inner shell is neutral. Find the charge that will flow from inner shell to earth after the switch S is closed.
Answer» Two conducting thin concentric shells of radii r and 3r is shown below. Inner shell is neutral. Find the charge that will flow from inner shell to earth after the switch S is closed.

16.

Two conducting thin concentric shells of radii r and 3r is shown below. Inner shell is neutral. Find the charge that will flow from inner shell to earth after the switch S is closed.

Answer»

Two conducting thin concentric shells of radii r and 3r is shown below. Inner shell is neutral. Find the charge that will flow from inner shell to earth after the switch S is closed.

Discussion

17.	If a man at the equator would weigh (35)th of his weight, the angular speed of the earth is.
Answer» If a man at the equator would weigh ${(\frac{3}{5})}^{t h}$ of his weight, the angular speed of the earth is.

Discussion

18.	Why do gravity exist so strongly on earth
Answer» Why do gravity exist so strongly on earth

Discussion

19.	Which of the following curves shows correct relation between convective resistance (R) and radius of hot sphere (r) being placed in a stream of cold air ?
Answer» Which of the following curves shows correct relation between convective resistance $(R)$ and radius of hot sphere $(r)$ being placed in a stream of cold air ?

Discussion

20.	If a body or a surface is considered to have electric flux should it contain charge particularly in addition to the number of lines of force entering and leaving it?
Answer» If a body or a surface is considered to have electric flux should it contain charge particularly in addition to the number of lines of force entering and leaving it?

Discussion

21.	What is capacitance and capacitor?
Answer» What is capacitance and capacitor?

Discussion

22.	The sum!of N coplanar from each other of magnitude F when each force makes an angle (2* pi)/N with the proceeding one??
Answer» The sum!of N coplanar from each other of magnitude F when each force makes an angle (2* pi)/N with the proceeding one??

Discussion

23.	A stone is released from an elevator going up with an acceleration a.The acceleration of the stone after the release is ?
Answer» A stone is released from an elevator going up with an acceleration a.The acceleration of the stone after the release is ?

Discussion

24.	A flat plate is separated from a large plate by a layer of glycerine of thickness 3 X 10-3m. If the co-efficient of viscocity of glycerine is 2 Nsm2, what is the force required to keep the plate moving with a velocity of 6 X 10-2 m/s. Area of the plate is 4.8 X 10-3m2.
Answer» A flat plate is separated from a large plate by a layer of glycerine of thickness 3 X 10^-3m. If the co-efficient of viscocity of glycerine is 2 Nsm², what is the force required to keep the plate moving with a velocity of 6 X 10^-2m/s. Area of the plate is 4.8 X 10^-3m².

Discussion

25.	Remaining question Total time for (n) oscillatios(s) \| Time period (s) 128.0 \| 16.0 64.0 \| 16.0 36.0 \| 9.0 I didnt get the question itself plz explain me the question and then the answer
Answer» Remaining question Total time for (n) oscillatios(s) \| Time period (s) 128.0 \| 16.0 64.0 \| 16.0 36.0 \| 9.0 I didnt get the question itself plz explain me the question and then the answer

Discussion

26.	What is source of em wave
Answer» What is source of em wave

Discussion

27.	Block A of mass m and block B of mass 2m are placed on a fixed tringular wedge by means of a massless inextensible string and a frictionless pulley as shown in figure . The wedge is inclined at 45∘ to the horizointal on both sides. If the coefficient of friction between the block A and the wedge is 23 and that between block B and the wedge is 13 and both the blocks A and B are released from rest, the acceleration of A will be
Answer» Block A of mass $m$ and block $B$ of mass $2 m$ are placed on a fixed tringular wedge by means of a massless inextensible string and a frictionless pulley as shown in figure . The wedge is inclined at $45^{\circ}$ to the horizointal on both sides. If the coefficient of friction between the block $A$ and the wedge is $\frac{2}{3}$ and that between block B and the wedge is $\frac{1}{3}$ and both the blocks $A$ and $B$ are released from rest, the acceleration of $A$ will be

Discussion

28.	The temperature of water at the surface of a deep lake is 2∘C. The temperature expected at the bottom is.(Lake is deep enough)
Answer» The temperature of water at the surface of a deep lake is $2^{\circ} C$ . The temperature expected at the bottom is.(Lake is deep enough)

Discussion

29.	A 40 cm wire having a mass of 3.2 g is stretched between two fixed supports 40.05 cm apart. In its fundamental mode, the wire vibrates at 220 Hz. If the area of cross section of the wire is 1.0 mm2, find its Young modulus.
Answer» A 40 cm wire having a mass of 3.2 g is stretched between two fixed supports 40.05 cm apart. In its fundamental mode, the wire vibrates at 220 Hz. If the area of cross section of the wire is $1.0 m m^{2}$ , find its Young modulus.

Discussion

30.	Comment on the correctness of the following two statements: Statement I => Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution. Statement II => Gauss’s law is valid only for charges placed in vacuum.
Answer» Comment on the correctness of the following two statements: Statement I => Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution. Statement II => Gauss’s law is valid only for charges placed in vacuum.

30.

Comment on the correctness of the following two statements: Statement I => Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution. Statement II => Gauss’s law is valid only for charges placed in vacuum.

Answer»

Comment on the correctness of the following two statements:

Statement I => Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution.

Statement II => Gauss’s law is valid only for charges placed in vacuum.

Discussion

31.	Seven capacitors each of capacitance 2 μF are connected in a configuration to obtain an effective capacitance 1011μF. Which of the following combination will achieve the desired result?
Answer» Seven capacitors each of capacitance $2 μ F$ are connected in a configuration to obtain an effective capacitance $\frac{10}{11} μ F$ . Which of the following combination will achieve the desired result?

Discussion

32.	While charging a metallic sphere negatively by induction by bringing a positively charged rod near it the electrons will flow from the ground to the sphere when the sphere is connected to the ground with a wire. WHY DOES THIS HAPPEN?
Answer» While charging a metallic sphere negatively by induction by bringing a positively charged rod near it the electrons will flow from the ground to the sphere when the sphere is connected to the ground with a wire. WHY DOES THIS HAPPEN?

Discussion

33.	Two bodies are projected with the same velocity. If one is projected at an angle of 30∘ and the other at an angle of 60∘ to the horizontal, the ratio of the maximum heights reached is
Answer» Two bodies are projected with the same velocity. If one is projected at an angle of $30^{\circ}$ and the other at an angle of $60^{\circ}$ to the horizontal, the ratio of the maximum heights reached is

Discussion

34.	What does potential difference in a capacitor really mean? Is it the work done in bringing Q charge from infinity?
Answer» What does potential difference in a capacitor really mean? Is it the work done in bringing Q charge from infinity?

Discussion

35.	An opaque sphere of radius a is just immersed in a transparent liquid as shown in figure. A point source is placed on the vertical diameter of the sphere at a distance a2 from the top of the sphere. A ray from the point source after refraction from the air liquid interface forms tangent to the sphere. The angle of refraction for that particular ray is 30∘. The refractive index of the liquid is
Answer» An opaque sphere of radius $a$ is just immersed in a transparent liquid as shown in figure. A point source is placed on the vertical diameter of the sphere at a distance $\frac{a}{2}$ from the top of the sphere. A ray from the point source after refraction from the air liquid interface forms tangent to the sphere. The angle of refraction for that particular ray is $30^{\circ}$ . The refractive index of the liquid is

Discussion

36.	The wave length of light having wave number 4000 cm−1 is
Answer» The wave length of light having wave number $4000 c m^{- 1}$ is

Discussion

37.	Two balls marked 1 and 2 of the same mass m and a third ball marked 3 of mass M are arranged over a smooth horizontal surface as shown in the figure. Ball 1 moves with a velocity v1 towards balls 2 and 3. All collisions are assumed to be elastic. If M < m, the number of collisions between the balls will be
Answer» Two balls marked 1 and 2 of the same mass m and a third ball marked 3 of mass M are arranged over a smooth horizontal surface as shown in the figure. Ball 1 moves with a velocity $v_{1}$ towards balls 2 and 3. All collisions are assumed to be elastic. If M < m, the number of collisions between the balls will be

Discussion

38.	An electron in a hydrogen atom makes a transition from n=n1 to n=n2. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are
Answer» An electron in a hydrogen atom makes a transition from $n = n_{1}$ to $n = n_{2}$ . The time period of the electron in the initial state is eight times that in the final state. The possible values of $n_{1}$ and $n_{2}$ are

Discussion

39.	A certain ideal gas undergoes a polytropic process represented by equation PVn=constant. If Molar heat capacity for this process is negative and γ is a standard constant which denotes the ratio of the molar heat capacities of a gas, then the range of values of n will be
Answer» A certain ideal gas undergoes a polytropic process represented by equation $P V^{n} = constant$ . If Molar heat capacity for this process is negative and $γ$ is a standard constant which denotes the ratio of the molar heat capacities of a gas, then the range of values of $n$ will be

Discussion

40.	A person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is δT=0.01 seconds and he measures the depth of the well to be L=20 meters. Take the acceleration due to gravity g=10 ms−2 and the velocity of sound is 300 ms−1. Then the fractional error in the measurement, δL/L, is closest to
Answer» A person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is $δ T = 0.01$ seconds and he measures the depth of the well to be $L = 20$ meters. Take the acceleration due to gravity $g = 10 m s^{- 2}$ and the velocity of sound is $300 m s^{- 1}$ . Then the fractional error in the measurement, $δ L / L$ , is closest to

Discussion

41.	An ideal liquid is streamline motion flows through a frictionless duct with varying cross-section as shown in figure. Pressure P at points along the x axis of duct is most likely to be represented by :
Answer» An ideal liquid is streamline motion flows through a frictionless duct with varying cross-section as shown in figure. Pressure P at points along the x axis of duct is most likely to be represented by :

41.

An ideal liquid is streamline motion flows through a frictionless duct with varying cross-section as shown in figure. Pressure P at points along the x axis of duct is most likely to be represented by :

Answer»

An ideal liquid is streamline motion flows through a frictionless duct with varying cross-section as shown in figure.

Pressure P at points along the x axis of duct is most likely to be represented by :

Discussion

42.	A particle is projected upwards from top of a tower of height 40 m with a speed of 10 m/s. The time it will take to strike ground (g=10 m/s2) will be
Answer» A particle is projected upwards from top of a tower of height $40 m$ with a speed of $10 m / s$ . The time it will take to strike ground $(g = 10 m / s^{2})$ will be

Discussion

43.	If electric field lines cross each other that would mean
Answer» If electric field lines cross each other that would mean

Discussion

44.	If y = x2 + 2x − 3, y-x graph is
Answer» If $y = x^{2} + 2 x - 3$ , y-x graph is

Discussion

45.	For the rotating container shown in figure, differences in the heights of the fluid between the centre and the sides (in cm) is- [Take π2=10 & g=10 m/s2 for calculation]
Answer» For the rotating container shown in figure, differences in the heights of the fluid between the centre and the sides (in $cm$ ) is- [Take $π^{2} = 10 & g = 10 {m/s}^{2}$ for calculation]

Discussion

46.	A proton and an α - particle accelerated through the same potential difference enter a region of uniform magnet field normally. If the radius of proton orbit is 10 cm then radius of α - particle orbit is
Answer» A proton and an $α$ - particle accelerated through the same potential difference enter a region of uniform magnet field normally. If the radius of proton orbit is 10 cm then radius of $α$ - particle orbit is

Discussion

47.	A body of density d1 is counterpoised by Mg of weights of density d2 in air of density d. Then the true mass of the body is
Answer» A body of density $d_{1}$ is counterpoised by Mg of weights of density $d_{2}$ in air of density d. Then the true mass of the body is

Discussion

48.	A truck moving at 72 km/hr carries a steel girder which rests on its wooden floor.what is the time in which the truck can come to stop without the girder moving forward,the co-efficient of friction is 0.5
Answer» A truck moving at 72 km/hr carries a steel girder which rests on its wooden floor.what is the time in which the truck can come to stop without the girder moving forward,the co-efficient of friction is 0.5

Discussion

49.	In a certain circuit current changes with time according to i=2√t. r.m.s. value of current between t=2 to t=4s will be
Answer» In a certain circuit current changes with time according to $i = 2 \sqrt{t} .$ r.m.s. value of current between t=2 to t=4s will be

49.

In a certain circuit current changes with time according to i=2√t. r.m.s. value of current between t=2 to t=4s will be

Answer»

In a certain circuit current changes with time according to $i = 2 \sqrt{t} .$ r.m.s. value of current between t=2 to t=4s will be

Discussion

50.	Figure (10-E4) shows two blocks of masses m and M connected by a string passing over a pulley. The horizontal table over which the mass m slides is smooth. The pulley has a radius r and moment of inertia I about its axis and it can freely rotate about this axis. Find the acceleration of the mass M assuming that the string does not slip on the pulley.
Answer» Figure (10-E4) shows two blocks of masses m and M connected by a string passing over a pulley. The horizontal table over which the mass m slides is smooth. The pulley has a radius r and moment of inertia I about its axis and it can freely rotate about this axis. Find the acceleration of the mass M assuming that the string does not slip on the pulley.

50.

Figure (10-E4) shows two blocks of masses m and M connected by a string passing over a pulley. The horizontal table over which the mass m slides is smooth. The pulley has a radius r and moment of inertia I about its axis and it can freely rotate about this axis. Find the acceleration of the mass M assuming that the string does not slip on the pulley.

Answer»

Figure (10-E4) shows two blocks of masses m and M connected by a string passing over a pulley. The horizontal table over which the mass m slides is smooth. The pulley has a radius r and moment of inertia I about its axis and it can freely rotate about this axis. Find the acceleration of the mass M assuming that the string does not slip on the pulley.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If photons have no mass, how can they have momentum?

Focal length of equiconvex lens with radius of each surface being 30 cm and refractive index 1.5, is

The loudness and pitch of a sound depends on

A block is kept on a frictionless inclined surface with angle of inclination ′α′. The incline is given an acceleration 'a' to keep the block stationary. Then a is equal to

V-u = distance travelled is correct or not .

Using figure (22.1), find the relative luminosity of wavelength (a) 480 nm, (b)520 nm (c) 580 nm and (d) 600 nm.

If the capacitance of each capacitor is C, then effective capacitance of the shown network across any two junctions is

Let ABCD be a trapezium with AD parallel to BC. Assume there is a point M in the interior of the segment BC such that AB = AM and DC = DM. Then the ratio of the area of the trapezium to the area of triangle AMD is.

The temperature of argon, kept in a vessel is raised by 1∘C at a constant volume. The total heat supplied to the gas is a combination of translational and rotational energies. Their respective shares are

Two particle A and B are moving with uniform velocity as shown in the figure given below at t =0. I. Will the two particle collide II. Find out shortest distance between two particles

What is the radius of curvature of a convex mirror if the focal length is 60 cm?

A body of mass 2 kg is projected with a speed 4 m/s at an angle 45∘ to the horizontal. What will be its angular momentum about the point of projection when the body is at the highest point in its trajectory?

Two conducting thin concentric shells of radii r and 3r is shown below. Inner shell is neutral. Find the charge that will flow from inner shell to earth after the switch S is closed.

If a man at the equator would weigh (35)th of his weight, the angular speed of the earth is.

Why do gravity exist so strongly on earth

Which of the following curves shows correct relation between convective resistance (R) and radius of hot sphere (r) being placed in a stream of cold air ?

If a body or a surface is considered to have electric flux should it contain charge particularly in addition to the number of lines of force entering and leaving it?

What is capacitance and capacitor?

The sum!of N coplanar from each other of magnitude F when each force makes an angle (2* pi)/N with the proceeding one??

A stone is released from an elevator going up with an acceleration a.The acceleration of the stone after the release is ?

A flat plate is separated from a large plate by a layer of glycerine of thickness 3 X 10-3m. If the co-efficient of viscocity of glycerine is 2 Nsm2, what is the force required to keep the plate moving with a velocity of 6 X 10-2 m/s. Area of the plate is 4.8 X 10-3m2.

Remaining question Total time for (n) oscillatios(s) | Time period (s) 128.0 | 16.0 64.0 | 16.0 36.0 | 9.0 I didnt get the question itself plz explain me the question and then the answer

What is source of em wave

The temperature of water at the surface of a deep lake is 2∘C. The temperature expected at the bottom is.(Lake is deep enough)

A 40 cm wire having a mass of 3.2 g is stretched between two fixed supports 40.05 cm apart. In its fundamental mode, the wire vibrates at 220 Hz. If the area of cross section of the wire is 1.0 mm2, find its Young modulus.

Comment on the correctness of the following two statements: Statement I =&gt; Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution. Statement II =&gt; Gauss’s law is valid only for charges placed in vacuum.

Seven capacitors each of capacitance 2 μF are connected in a configuration to obtain an effective capacitance 1011μF. Which of the following combination will achieve the desired result?

While charging a metallic sphere negatively by induction by bringing a positively charged rod near it the electrons will flow from the ground to the sphere when the sphere is connected to the ground with a wire. WHY DOES THIS HAPPEN?

Two bodies are projected with the same velocity. If one is projected at an angle of 30∘ and the other at an angle of 60∘ to the horizontal, the ratio of the maximum heights reached is

What does potential difference in a capacitor really mean? Is it the work done in bringing Q charge from infinity?

The wave length of light having wave number 4000 cm−1 is

An electron in a hydrogen atom makes a transition from n=n1 to n=n2. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are

A certain ideal gas undergoes a polytropic process represented by equation PVn=constant. If Molar heat capacity for this process is negative and γ is a standard constant which denotes the ratio of the molar heat capacities of a gas, then the range of values of n will be

An ideal liquid is streamline motion flows through a frictionless duct with varying cross-section as shown in figure. Pressure P at points along the x axis of duct is most likely to be represented by :

A particle is projected upwards from top of a tower of height 40 m with a speed of 10 m/s. The time it will take to strike ground (g=10 m/s2) will be

If electric field lines cross each other that would mean

If y = x2 + 2x − 3, y-x graph is

For the rotating container shown in figure, differences in the heights of the fluid between the centre and the sides (in cm) is- [Take π2=10 &amp; g=10 m/s2 for calculation]

A proton and an α - particle accelerated through the same potential difference enter a region of uniform magnet field normally. If the radius of proton orbit is 10 cm then radius of α - particle orbit is

A body of density d1 is counterpoised by Mg of weights of density d2 in air of density d. Then the true mass of the body is

A truck moving at 72 km/hr carries a steel girder which rests on its wooden floor.what is the time in which the truck can come to stop without the girder moving forward,the co-efficient of friction is 0.5

In a certain circuit current changes with time according to i=2√t. r.m.s. value of current between t=2 to t=4s will be

Comment on the correctness of the following two statements: Statement I => Gauss’s law is valid only for symmetrical Gaussian surfaces with respect to the charge distribution. Statement II => Gauss’s law is valid only for charges placed in vacuum.

For the rotating container shown in figure, differences in the heights of the fluid between the centre and the sides (in cm) is- [Take π2=10 & g=10 m/s2 for calculation]