50278 + Interview Questions in Physics

1.	A boat of area 10 m2 floating on the surface of a river is made to move horizontally with a speed of 2 m/s by applying a tangential force. If the river is 1 m deep and the water in contact with the bed is stationary, find the tangential force needed to keep the boat moving with same velocity. (Assume the viscosity of water as 0.01 poise).
Answer» A boat of area $10 m^{2}$ floating on the surface of a river is made to move horizontally with a speed of $2 m/s$ by applying a tangential force. If the river is $1 m$ deep and the water in contact with the bed is stationary, find the tangential force needed to keep the boat moving with same velocity. (Assume the viscosity of water as $0.01 poise$ ).

Discussion

2.	An electron and a proton are detected in a cosmic ray experiment, the first with kinetic energy 10 keV, and the second with 100 keV. Which is faster, the electron or the proton ? Obtain the ratio of their speeds. (electron mass = 9.11×10¯³¹ kg, proton mass = 1.67×10¯²⁷ kg, 1 eV = 1.60 ×10¯¹⁹ J).
Answer» An electron and a proton are detected in a cosmic ray experiment, the first with kinetic energy 10 keV, and the second with 100 keV. Which is faster, the electron or the proton ? Obtain the ratio of their speeds. (electron mass = 9.11×10¯³¹ kg, proton mass = 1.67×10¯²⁷ kg, 1 eV = 1.60 ×10¯¹⁹ J).

Discussion

3.	If a man jumps out of the boat in the forward direction, the boat will move
Answer» If a man jumps out of the boat in the forward direction, the boat will move

Discussion

4.	What do you mean by state of rest and motion.
Answer» What do you mean by state of rest and motion.

Discussion

5.	The velocity of a body of rest mass m0 is (where c is the velocity of light in vacuum). The mass of this body is
Answer» The velocity of a body of rest mass $m_{0}$ is (where c is the velocity of light in vacuum). The mass of this body is

Discussion

6.	The x−t graph of a particle undergoing simple harmonic motion is shown below. The acceleration of the particle at t=43 s is
Answer» The $x - t$ graph of a particle undergoing simple harmonic motion is shown below. The acceleration of the particle at $t = \frac{4}{3} s$ is

Discussion

7.	are strong nuclear forces always attractive
Answer» are strong nuclear forces always attractive

Discussion

8.	Can Chain Rule be also used in Integration ?
Answer» Can Chain Rule be also used in Integration ?

Discussion

9.	10. A ball is dropped from a height of 80 m on a floor At each collision ball losses half of its speed then the graph between speed v/s time is
Answer» 10. A ball is dropped from a height of 80 m on a floor At each collision ball losses half of its speed then the graph between speed v/s time is

Discussion

10.	A conducting rod of length l is hinged at point O. It is free to rotate in a vertical plane. There exists a uniform magnetic field →B in horizontal direction. The rod is released from the horizontal position. When the rod makes an angle θ with the initial position, the potential difference between two ends of the rod is proportional to -When the rod is in horizontal direction, the potential difference across its ends is zero.
Answer» A conducting rod of length $l$ is hinged at point $O$ . It is free to rotate in a vertical plane. There exists a uniform magnetic field $\to B$ in horizontal direction. The rod is released from the horizontal position. When the rod makes an angle $θ$ with the initial position, the potential difference between two ends of the rod is proportional to - When the rod is in horizontal direction, the potential difference across its ends is zero.

Discussion

11.	So it takes ugsecs to go up, how long will it take to come down?(as mentioned there is no air)
Answer» So it takes $\frac{u}{g}$ secs to go up, how long will it take to come down?(as mentioned there is no air)

Discussion

12.	A wooden stick of length 100 cm is floating in water while remaining vertical. The relative density of the wood is 0.7. The apparent length of the stick when viewed from top [close to the vertical line along the stick] is x cm. Find x/10. Refractive index of water =43 (Write upto two digits after the decimal point.)
Answer» A wooden stick of length $100 c m$ is floating in water while remaining vertical. The relative density of the wood is 0.7. The apparent length of the stick when viewed from top [close to the vertical line along the stick] is $x c m$ . Find $x / 10$ . Refractive index of water $= \frac{4}{3}$ (Write upto two digits after the decimal point.)

Discussion

13.	In LC OSCILLATION maximum charge on capacitor can be Q.if at any instant , electric energy and magnetic energy associated with circit is equal ,then charge on capacitor at that instant is
Answer» In LC OSCILLATION maximum charge on capacitor can be Q.if at any instant , electric energy and magnetic energy associated with circit is equal ,then charge on capacitor at that instant is

Discussion

14.	An aluminium rod of length 3.14 m is of square cross-section 3.14×3.14 mm2. What should be the radius of 1 m long another rod of same material to have equal resistance
Answer» An aluminium rod of length 3.14 m is of square cross-section $3.14 \times 3.14 m m^{2}$ . What should be the radius of 1 m long another rod of same material to have equal resistance

Discussion

15.	What do we call the gravitational force between the earth and an object?
Answer» What do we call the gravitational force between the earth and an object?

Discussion

16.	A cuboidal body of dimensions 2 m × 3 m × 4 m is acted upon by a perpendicular force of 50 N on the top surface (2 m × 3 m) as shown in the figure. Calculate the pressure due to the force on that surface.
Answer» A cuboidal body of dimensions 2 m $\times$ 3 m $\times$ 4 m is acted upon by a perpendicular force of 50 N on the top surface (2 m $\times$ 3 m) as shown in the figure. Calculate the pressure due to the force on that surface.

Discussion

17.	14. A particle is projected vertically upward and it covers a distance of 10 m in its 5th second. The maximum height attained by the particle is
Answer» 14. A particle is projected vertically upward and it covers a distance of 10 m in its 5th second. The maximum height attained by the particle is

Discussion

18.	The coefficient of static friction between the bodies A and B is 0.3. Determine minimum stopping distance that the body A can travel if it has initial speed of 70 km/h with constant retardation and the body B is not to slip forward.
Answer» The coefficient of static friction between the bodies $A$ and $B$ is $0.3$ . Determine minimum stopping distance that the body $A$ can travel if it has initial speed of $70 km/h$ with constant retardation and the body $B$ is not to slip forward.

Discussion

19.	A cricketer catches a ball of mass 150g in 0.1s moving with speed 20m/sec then he experiences force o
Answer» A cricketer catches a ball of mass 150g in 0.1s moving with speed 20m/sec then he experiences force o

Discussion

20.	Why the line emission spectrum of Hydrogen contains so many lines although it has only one electron?
Answer» Why the line emission spectrum of Hydrogen contains so many lines although it has only one electron?

Discussion

21.	Diameter of the moon is 3.5×103 km and its distance from the earth is 3.8×105 km. It is seen by a telescope whose objective and eyepiece have focal lengths 4 m and 10 cm respectively. The angular diameter of the image of the moon is (assume final image is at infinity)
Answer» Diameter of the moon is $3.5 \times 10^{3} k m$ and its distance from the earth is $3.8 \times 10^{5} k m$ . It is seen by a telescope whose objective and eyepiece have focal lengths $4 m$ and $10 c m$ respectively. The angular diameter of the image of the moon is (assume final image is at infinity)

Discussion

22.	Two blocks of masses m and 2m are kept on a smooth horizontal surface. They are connected by an ideal spring of force constant k. Initially the spring is unstretched. A constant force is applied to the heavier block in the direction shown in figure. Suppose at time t displacement of smaller block is x, then displacement of the heavier block at this moment would be:
Answer» Two blocks of masses $m$ and $2 m$ are kept on a smooth horizontal surface. They are connected by an ideal spring of force constant $k$ . Initially the spring is unstretched. A constant force is applied to the heavier block in the direction shown in figure. Suppose at time $t$ displacement of smaller block is $x$ , then displacement of the heavier block at this moment would be:

Discussion

23.	A magnet of magnetic moment M is situated with its axis along the direction of a magnetic field of strength B. The work done in rotating it by an angle of 180∘ will be
Answer» A magnet of magnetic moment $M$ is situated with its axis along the direction of a magnetic field of strength $B$ . The work done in rotating it by an angle of $180^{\circ}$ will be

Discussion

24.	On an inclined plane inclined at an angle of 30° to the horizontal, a ball is thrown upwards with a velocity of 10 m/s, at an angle of 60° to the inclined plane. Its range on the inclined plane is
Answer» On an inclined plane inclined at an angle of 30° to the horizontal, a ball is thrown upwards with a velocity of 10 m/s, at an angle of 60° to the inclined plane. Its range on the inclined plane is

Discussion

25.	A smooth tunnel is dug along the radius of earth that ends at centre. A ball is released from the surface of earth along tunnel. Coefficient of restitution for collision between soil at centre and ball is 0.5. Calculate the distance travelled by ball just before second collision at centre. Given mass of the earth is M and radius of the earth is R.
Answer» A smooth tunnel is dug along the radius of earth that ends at centre. A ball is released from the surface of earth along tunnel. Coefficient of restitution for collision between soil at centre and ball is $0.5$ . Calculate the distance travelled by ball just before second collision at centre. Given mass of the earth is $M$ and radius of the earth is $R$ .

Discussion

26.	Which one of the following is smallest in size ?
Answer» Which one of the following is smallest in size ?

Discussion

27.	process of formation of protongradient in lamell
Answer» process of formation of protongradient in lamell

Discussion

28.	A boy riding a bicycle with a speed of 4 m/s towards east direction, observes rain falling vertically downward. If he increases his speed to 8 m/s, rain appears to meet him at 45^° to the vertical. The speed of rain with repect to ground is (1) 8 m/s (2) 4 m/s (3) 4\surd2 m/s (4) 2 m/s
Answer» A boy riding a bicycle with a speed of 4 m/s towards east direction, observes rain falling vertically downward. If he increases his speed to 8 m/s, rain appears to meet him at 45^° to the vertical. The speed of rain with repect to ground is (1) 8 m/s (2) 4 m/s (3) 4\surd2 m/s (4) 2 m/s

Discussion

29.	Which of the following statements are incorrect regarding the Bohr's Atomic Model ?
Answer» Which of the following statements are incorrect regarding the Bohr's Atomic Model ?

Discussion

30.	A point object is moving with speed v in front of the arrangement of two perpendicular plane mirrors as shown in the figure. The magnitude of velocity of image in mirror M1 with respect to image in mirror M2 will be
Answer» A point object is moving with speed $v$ in front of the arrangement of two perpendicular plane mirrors as shown in the figure. The magnitude of velocity of image in mirror $M_{1}$ with respect to image in mirror $M_{2}$ will be

Discussion

31.	A body is moving with velocity 30m/s towards east. After 10 seconds its velocity becomes 40m/s towards north. The average acceleration of the body is (Answer coming is 5m/S2)
Answer» A body is moving with velocity 30m/s towards east. After 10 seconds its velocity becomes 40m/s towards north. The average acceleration of the body is (Answer coming is 5m/S2)

Discussion

32.	A BODY IS THROWN VERTICALLY UPWARDS WITH A VELOCITY OF 10km/s FROM THE EARTHS SURFACE. UP TO WHICH HEIGHT IT WILL GO? RADIUS OF EARTH IS 6400km AND g = 10 metre per second square.
Answer» A BODY IS THROWN VERTICALLY UPWARDS WITH A VELOCITY OF 10km/s FROM THE EARTHS SURFACE. UP TO WHICH HEIGHT IT WILL GO? RADIUS OF EARTH IS 6400km AND g = 10 metre per second square.

Discussion

33.	An isotope of hydrogen atom is represented as X which follows Bohr’s model and exists as diatomic gaseous molecule X2. Also the normal boiling point of a compound X2O liquid is found to be 1010C and that of a solution obtained on dissolving 0.1 moles of NaCl in 1 kg of X2O liquid is 101.40C. It is also known that the ionization energy of X is equal to 14 eV. The value of ebullioscopic constant of X2O is:
Answer» An isotope of hydrogen atom is represented as X which follows Bohr’s model and exists as diatomic gaseous molecule $X_{2}$ . Also the normal boiling point of a compound $X_{2} O$ liquid is found to be $101^{0}$ C and that of a solution obtained on dissolving 0.1 moles of NaCl in 1 kg of $X_{2} O$ liquid is ${101.4}^{0}$ C. It is also known that the ionization energy of X is equal to 14 eV. The value of ebullioscopic constant of $X_{2} O$ is:

33.

An isotope of hydrogen atom is represented as X which follows Bohr’s model and exists as diatomic gaseous molecule X2. Also the normal boiling point of a compound X2O liquid is found to be 1010C and that of a solution obtained on dissolving 0.1 moles of NaCl in 1 kg of X2O liquid is 101.40C. It is also known that the ionization energy of X is equal to 14 eV. The value of ebullioscopic constant of X2O is:

Answer»

An isotope of hydrogen atom is represented as X which follows Bohr’s model and exists as diatomic gaseous molecule $X_{2}$ . Also the normal boiling point of a compound $X_{2} O$ liquid is found to be $101^{0}$ C and that of a solution obtained on dissolving 0.1 moles of NaCl in 1 kg of $X_{2} O$ liquid is ${101.4}^{0}$ C. It is also known that the ionization energy of X is equal to 14 eV.

The value of ebullioscopic constant of $X_{2} O$ is:

Discussion

34.	62. If a particle is accelerated for a time t1 with acceleration a1 and for time t2 with acceleration a2. Then average acceleration is??
Answer» 62. If a particle is accelerated for a time t1 with acceleration a1 and for time t2 with acceleration a2. Then average acceleration is??

Discussion

35.	The coefficient of static friction between the two blocks is 0.363. What is the minimum acceleration(approximate value) of block 1 so that block 2 does not fall?
Answer» The coefficient of static friction between the two blocks is 0.363. What is the minimum acceleration(approximate value) of block 1 so that block 2 does not fall?

Discussion

36.	12.ermangnet ion is Options: Diamagnetic in nature Paramagnetic in nature Weak paramagnetic nature None of these
Answer» 12.ermangnet ion is Options: Diamagnetic in nature Paramagnetic in nature Weak paramagnetic nature None of these

Discussion

37.	A man thinks about 4 arrangements as shown to raise two small bricks each having mass m. Which of the arrangement would take minimum time for the same force applied ?
Answer» A man thinks about 4 arrangements as shown to raise two small bricks each having mass $m$ . Which of the arrangement would take minimum time for the same force applied ?

Discussion

38.	Two bodies of masses 1 kg and 3 kg are tied at the tweends of a thread of length 60 cm and the arrangementis kept diametrically on a table. If the table is rotatedabout an axis passing through its centre, then it isobserved that no motion in the thread is generatedalong the diameter. What is the distance of the Igmass from the centre of the table?bSW
Answer» Two bodies of masses 1 kg and 3 kg are tied at the tweends of a thread of length 60 cm and the arrangementis kept diametrically on a table. If the table is rotatedabout an axis passing through its centre, then it isobserved that no motion in the thread is generatedalong the diameter. What is the distance of the Igmass from the centre of the table?bSW

Discussion

39.	A spherical black body of radius 12 cm radiates 450 W power at 500 K. If the radius were halved and the temperature doubled, the power radiated would be
Answer» A spherical black body of radius 12 cm radiates 450 W power at 500 K. If the radius were halved and the temperature doubled, the power radiated would be

Discussion

40.	42. If velocity of electron becomes equal to the velocity of light, then mass of electron will be- decreased Infinity remains same zero
Answer» 42. If velocity of electron becomes equal to the velocity of light, then mass of electron will be- decreased Infinity remains same zero

Discussion

41.	A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 m/s2, speed of sound = 340 m/s
Answer» A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 $m / s^{2}$ , speed of sound = 340 m/s

Discussion

42.	If →a=2^i+3^j,→b=^i+^j+^k,→c=λ^i+4^j+2^k are coterminous edges of a parallelopiped of volume 2 cubic units, then λ is
Answer» If $\to a = 2^i + 3^j, \to b =^i +^j +^k, \to c = λ^i + 4^j + 2^k$ are coterminous edges of a parallelopiped of volume $2$ cubic units, then $λ$ is

Discussion

43.	A particle executes SHM with a period of 16 s. At time t=2s, the particle crosses the mean position while at t=4s, it's velocity is 4 m/s. Amplitude of motion in metre is
Answer» A particle executes SHM with a period of 16 s. At time t=2s, the particle crosses the mean position while at t=4s, it's velocity is 4 m/s. Amplitude of motion in metre is

Discussion

44.	80 gm of water at 30∘C are poured on a large block of ice at 0∘C. The mass of ice that melts is
Answer» 80 gm of water at $30^{\circ} C$ are poured on a large block of ice at $0^{\circ} C$ . The mass of ice that melts is

Discussion

45.	A glass hemisphere of refractive index 4/3 and radius 4 cm is placed on a plane mirror. A point object is placed at distance ′d′ on the axis of this sphere as shown. If the final image is at infinity, then the value of ′d′ in cm is
Answer» A glass hemisphere of refractive index $4 / 3$ and radius $4 cm$ is placed on a plane mirror. A point object is placed at distance $^{'} d^{'}$ on the axis of this sphere as shown. If the final image is at infinity, then the value of $^{'} d^{'}$ in $cm$ is

Discussion

46.	An infinite conducting sheet has surface chargedensity σ. The distance between two equipotentialsurfaces is r. The potential difference betweenthese two surfaces is
Answer» An infinite conducting sheet has surface chargedensity σ. The distance between two equipotentialsurfaces is r. The potential difference betweenthese two surfaces is

Discussion

47.	Two cars A and B are moving with uniform speeds as shown in the figure given below, at t=0. Find out the shortest distance between the two cars.
Answer» Two cars $A$ and $B$ are moving with uniform speeds as shown in the figure given below, at $t = 0$ . Find out the shortest distance between the two cars.

Discussion

48.	2) A stone is dropped from the window of a bus at 60km/hr.if the window is 1.96m high,find the distance along the track which the stone moves before striking the ground.
Answer» 2) A stone is dropped from the window of a bus at 60km/hr.if the window is 1.96m high,find the distance along the track which the stone moves before striking the ground.

Discussion

49.	A uniform solid hemisphere of radius r is joined to a uniform solid right circular coneof base r and height \sqrt{3r.if both have same density then find position of centre of mass from the centre of hemisphere
Answer» A uniform solid hemisphere of radius r is joined to a uniform solid right circular coneof base r and height \sqrt{3r.if both have same density then find position of centre of mass from the centre of hemisphere

Discussion

50.	13. Yellow light emitted from a potasium lamp has a wave length of 850 nm.Calculate the frequency nd wavenumber of this yellow light.
Answer» 13. Yellow light emitted from a potasium lamp has a wave length of 850 nm.Calculate the frequency nd wavenumber of this yellow light.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If a man jumps out of the boat in the forward direction, the boat will move

What do you mean by state of rest and motion.

The velocity of a body of rest mass m0 is (where c is the velocity of light in vacuum). The mass of this body is

The x−t graph of a particle undergoing simple harmonic motion is shown below. The acceleration of the particle at t=43 s is

are strong nuclear forces always attractive

Can Chain Rule be also used in Integration ?

10. A ball is dropped from a height of 80 m on a floor At each collision ball losses half of its speed then the graph between speed v/s time is

So it takes ugsecs to go up, how long will it take to come down?(as mentioned there is no air)

In LC OSCILLATION maximum charge on capacitor can be Q.if at any instant , electric energy and magnetic energy associated with circit is equal ,then charge on capacitor at that instant is

An aluminium rod of length 3.14 m is of square cross-section 3.14×3.14 mm2. What should be the radius of 1 m long another rod of same material to have equal resistance

What do we call the gravitational force between the earth and an object?

A cuboidal body of dimensions 2 m × 3 m × 4 m is acted upon by a perpendicular force of 50 N on the top surface (2 m × 3 m) as shown in the figure. Calculate the pressure due to the force on that surface.

14. A particle is projected vertically upward and it covers a distance of 10 m in its 5th second. The maximum height attained by the particle is

The coefficient of static friction between the bodies A and B is 0.3. Determine minimum stopping distance that the body A can travel if it has initial speed of 70 km/h with constant retardation and the body B is not to slip forward.

A cricketer catches a ball of mass 150g in 0.1s moving with speed 20m/sec then he experiences force o

Why the line emission spectrum of Hydrogen contains so many lines although it has only one electron?

Diameter of the moon is 3.5×103 km and its distance from the earth is 3.8×105 km. It is seen by a telescope whose objective and eyepiece have focal lengths 4 m and 10 cm respectively. The angular diameter of the image of the moon is (assume final image is at infinity)

A magnet of magnetic moment M is situated with its axis along the direction of a magnetic field of strength B. The work done in rotating it by an angle of 180∘ will be

On an inclined plane inclined at an angle of 30° to the horizontal, a ball is thrown upwards with a velocity of 10 m/s, at an angle of 60° to the inclined plane. Its range on the inclined plane is

Which one of the following is smallest in size ?

process of formation of protongradient in lamell

A boy riding a bicycle with a speed of 4 m/s towards east direction, observes rain falling vertically downward. If he increases his speed to 8 m/s, rain appears to meet him at 45^° to the vertical. The speed of rain with repect to ground is (1) 8 m/s (2) 4 m/s (3) 4\surd2 m/s (4) 2 m/s

Which of the following statements are incorrect regarding the Bohr's Atomic Model ?

A point object is moving with speed v in front of the arrangement of two perpendicular plane mirrors as shown in the figure. The magnitude of velocity of image in mirror M1 with respect to image in mirror M2 will be

A body is moving with velocity 30m/s towards east. After 10 seconds its velocity becomes 40m/s towards north. The average acceleration of the body is (Answer coming is 5m/S2)

A BODY IS THROWN VERTICALLY UPWARDS WITH A VELOCITY OF 10km/s FROM THE EARTHS SURFACE. UP TO WHICH HEIGHT IT WILL GO? RADIUS OF EARTH IS 6400km AND g = 10 metre per second square.

62. If a particle is accelerated for a time t1 with acceleration a1 and for time t2 with acceleration a2. Then average acceleration is??

The coefficient of static friction between the two blocks is 0.363. What is the minimum acceleration(approximate value) of block 1 so that block 2 does not fall?

12.ermangnet ion is Options: Diamagnetic in nature Paramagnetic in nature Weak paramagnetic nature None of these

A man thinks about 4 arrangements as shown to raise two small bricks each having mass m. Which of the arrangement would take minimum time for the same force applied ?

A spherical black body of radius 12 cm radiates 450 W power at 500 K. If the radius were halved and the temperature doubled, the power radiated would be

42. If velocity of electron becomes equal to the velocity of light, then mass of electron will be- decreased Infinity remains same zero

A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 m/s2, speed of sound = 340 m/s

If →a=2^i+3^j,→b=^i+^j+^k,→c=λ^i+4^j+2^k are coterminous edges of a parallelopiped of volume 2 cubic units, then λ is

A particle executes SHM with a period of 16 s. At time t=2s, the particle crosses the mean position while at t=4s, it's velocity is 4 m/s. Amplitude of motion in metre is

80 gm of water at 30∘C are poured on a large block of ice at 0∘C. The mass of ice that melts is

A glass hemisphere of refractive index 4/3 and radius 4 cm is placed on a plane mirror. A point object is placed at distance ′d′ on the axis of this sphere as shown. If the final image is at infinity, then the value of ′d′ in cm is

An infinite conducting sheet has surface chargedensity σ. The distance between two equipotentialsurfaces is r. The potential difference betweenthese two surfaces is

Two cars A and B are moving with uniform speeds as shown in the figure given below, at t=0. Find out the shortest distance between the two cars.

2) A stone is dropped from the window of a bus at 60km/hr.if the window is 1.96m high,find the distance along the track which the stone moves before striking the ground.

A uniform solid hemisphere of radius r is joined to a uniform solid right circular coneof base r and height \sqrt{3r.if both have same density then find position of centre of mass from the centre of hemisphere

13. Yellow light emitted from a potasium lamp has a wave length of 850 nm.Calculate the frequency nd wavenumber of this yellow light.