50278 + Interview Questions in Physics Page 84 InterviewSolution

4151.	A bar magnet of magnetic moment 6 J/T is aligned at 600 with a uniform external magnetic field of 0.44 T. Calculate (a) the work done in turning the magnet to align its magnetic moment (i) normal to the magnetic field, (ii) opposite to the magnetic field, and (b) the torque on the magnet in the final orientation in case (ii).
Answer» A bar magnet of magnetic moment 6 J/T is aligned at $60^{0}$ with a uniform external magnetic field of 0.44 T. Calculate (a) the work done in turning the magnet to align its magnetic moment (i) normal to the magnetic field, (ii) opposite to the magnetic field, and (b) the torque on the magnet in the final orientation in case (ii).

Discussion

4152.	A body of mass 1 kg rests on a horizontal floor with which it has a coefficient of static friction1√3. It is desired to make the body move by applying the minimum possible force F N. The value of F will be . (Round off to the Nearest Integer)[Take g =10 ms2]
Answer» A body of mass $1 kg$ rests on a horizontal floor with which it has a coefficient of static friction $\frac{1}{\sqrt{3}}$ . It is desired to make the body move by applying the minimum possible force $F N$ . The value of $F$ will be . (Round off to the Nearest Integer)[Take g = $10 {ms}^{2}]$

Discussion

4153.	Two identical blocks of weight W are placed one on top of the other as shown in the figure. The upper block is tied to the wall. The coefficient of static friciton between B and the ground is μ and there is no friction between A and B. When F=μW force is applied on the lower block as shown, the tension in the string will be
Answer» Two identical blocks of weight $W$ are placed one on top of the other as shown in the figure. The upper block is tied to the wall. The coefficient of static friciton between $B$ and the ground is $μ$ and there is no friction between $A$ and $B$ . When $F = μ W$ force is applied on the lower block as shown, the tension in the string will be

Discussion

4154.	Suppose the initial charge on the capacitor in Exercise 7.7 is 6 mC.What is the total energy stored in the circuit initially? What is the total energy at later time?
Answer» Suppose the initial charge on the capacitor in Exercise 7.7 is 6 mC.What is the total energy stored in the circuit initially? What is the total energy at later time?

Discussion

4155.	The ratio to radii of curvature of a biconvex lens R1:R2 = 2 : 3. Its refractive index and focal length is 1.5 and 12 cm respectively. What is the value of R1? Consider R1 and R2 are positive and negative respectively.
Answer» The ratio to radii of curvature of a biconvex lens $R_{1} : R_{2}$ = 2 : 3. Its refractive index and focal length is $1.5$ and $12 c m$ respectively. What is the value of $R_{1}$ ? Consider $R_{1}$ and $R_{2}$ are positive and negative respectively.

Discussion

4156.	There is a shell of mass M, outer radius 2R and inner radius R. If gravitational field due to M4 (shaded part) at center of shell is →g, then field due to remaining part at center is
Answer» There is a shell of mass $M$ , outer radius $2 R$ and inner radius $R$ . If gravitational field due to $\frac{M}{4}$ (shaded part) at center of shell is $\to g$ , then field due to remaining part at center is

Discussion

4157.	Which electric field is responsible for the proton’s trajectory as shown below?
Answer» Which electric field is responsible for the proton’s trajectory as shown below?

4157.

Which electric field is responsible for the proton’s trajectory as shown below?

Answer»

Which electric field is responsible for the proton’s trajectory as shown below?

Discussion

4158.	25. For head-on collision between two colliding balls ofequal radii r, the impact parameter is equal to(1) 2r(2) Zero(3) More than 2r(4) Less than 2r
Answer» 25. For head-on collision between two colliding balls ofequal radii r, the impact parameter is equal to(1) 2r(2) Zero(3) More than 2r(4) Less than 2r

Discussion

4159.	6.The water drops are falling at regular intervals from the tap which is h m about the ground. the III drop is about to leave the tap when first drop touches the ground if the distance between the second drop and first drop is 3. 75 m then what is the height h ?
Answer» 6.The water drops are falling at regular intervals from the tap which is h m about the ground. the III drop is about to leave the tap when first drop touches the ground if the distance between the second drop and first drop is 3. 75 m then what is the height h ?

Discussion

4160.	Define vector 0 and give two examples.
Answer» Define vector 0 and give two examples.

Discussion

4161.	What is wavelength intensity relationship?
Answer» What is wavelength intensity relationship?

Discussion

4162.	41. There are two charges +2uC and -3uC.the ratio of forces acting on them will be
Answer» 41. There are two charges +2uC and -3uC.the ratio of forces acting on them will be

Discussion

4163.	A block of mass 15 kg is placed on a long trolley. The coefficient of static friction between the block and the trolley is 0.18. The trolley accelerates from rest with 0.5 m s¯² for 20 s and then moves with uniform velocity. Discuss the motion of the block as viewed by (a) a stationary observer on the ground, (b) an observer moving with the trolley.
Answer» A block of mass 15 kg is placed on a long trolley. The coefficient of static friction between the block and the trolley is 0.18. The trolley accelerates from rest with 0.5 m s¯² for 20 s and then moves with uniform velocity. Discuss the motion of the block as viewed by (a) a stationary observer on the ground, (b) an observer moving with the trolley.

Discussion

4164.	Two radioactive samples 1 and 2 have half lives T1 and T2 (T1>T2) respectively. At t=0, the activity of 2 was twice the activity of 1. Their activity will become equal after a time
Answer» Two radioactive samples $1$ and $2$ have half lives $T_{1}$ and $T_{2} (T_{1} > T_{2})$ respectively. At $t = 0$ , the activity of $2$ was twice the activity of $1$ . Their activity will become equal after a time

Discussion

4165.	A quantity X is defined as the ratio of the angular to linear momentum of an object. Then the dimensions of X are -
Answer» A quantity X is defined as the ratio of the angular to linear momentum of an object. Then the dimensions of X are -

Discussion

4166.	A bob of a simple pendulum of mass m is projected horizontally with some speed from its lowest point such that the string will slack at a position where it makes an angle 60∘ with the upward vertical direction. Find the tension in the string at the lowest position.
Answer» A bob of a simple pendulum of mass $m$ is projected horizontally with some speed from its lowest point such that the string will slack at a position where it makes an angle $60^{\circ}$ with the upward vertical direction. Find the tension in the string at the lowest position.

Discussion

4167.	In figure (a square), identify the following vectors: (i) Equal
Answer» In figure (a square), identify the following vectors: (i) Equal

Discussion

4168.	moment of inertia of trinagular lamina along its vertex , centroid, and bas
Answer» moment of inertia of trinagular lamina along its vertex , centroid, and bas

Discussion

4169.	1) When will a concave lens behave like convex lens? 2) When will a convex lens behave like a concave lens?
Answer» 1) When will a concave lens behave like convex lens? 2) When will a convex lens behave like a concave lens?

Discussion

4170.	A block of mass 2 kg moving with speed 5 m/s collides with another block of mass 4 kg at rest. The lighter block comes to rest after the collision. Find the coefficient of restitution (e). (Neglect all other external force)
Answer» A block of mass $2 kg$ moving with speed $5 m/s$ collides with another block of mass $4 kg$ at rest. The lighter block comes to rest after the collision. Find the coefficient of restitution $(e)$ . (Neglect all other external force)

Discussion

4171.	53.What is centre of gravity and equilibrium and it's types define them
Answer» 53.What is centre of gravity and equilibrium and it's types define them

Discussion

4172.	13. 80gm SO2 react with 40gm O2. Identify limiting reagent ??
Answer» 13. 80gm SO2 react with 40gm O2. Identify limiting reagent ??

Discussion

4173.	How can wave theory explain Rectilinear Propogation of Light?
Answer» How can wave theory explain Rectilinear Propogation of Light?

Discussion

4174.	For the following logic gates circuit, what is the correct expression for its output?
Answer» For the following logic gates circuit, what is the correct expression for its output?

Discussion

4175.	A falling stone takes 0.2 sec to fall across a windowwhich is 1m high. From how far above the top of thewindow was the stone dr opped
Answer» A falling stone takes 0.2 sec to fall across a windowwhich is 1m high. From how far above the top of thewindow was the stone dr opped

Discussion

4176.	A stone dropped from the top of a tower is found to travel 5/9 of the height of the tower during the last second of its fall. The time of fall will be ? 1) 2sec 2) 3 sec 3) 4 sec 4) 5 sec
Answer» A stone dropped from the top of a tower is found to travel 5/9 of the height of the tower during the last second of its fall. The time of fall will be ? 1) 2sec 2) 3 sec 3) 4 sec 4) 5 sec

Discussion

4177.	If ∫(2x+3)dxx(x+1)(x+2)(x+3)+1=K−1f(x) where f(x) is of the form of ax2+bx+c and K is the constant of integration, then (a+b+c) equals
Answer» If $\int \frac{(2 x + 3) d x}{x (x + 1) (x + 2) (x + 3) + 1} = K - \frac{1}{f (x)}$ where $f (x)$ is of the form of $a x^{2} + b x + c$ and $K$ is the constant of integration, then $(a + b + c)$ equals

Discussion

4178.	A photon detector receives a total of 3.15 X 10^-8 J from the radiation of 600 nm. Calculate the number of photons received
Answer» A photon detector receives a total of 3.15 X 10^-8 J from the radiation of 600 nm. Calculate the number of photons received

Discussion

4179.	Question 29Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?
Answer» Question 29 Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?

Discussion

4180.	How does an aspirator works ,which is an application of Bernoulli's principle?????
Answer» How does an aspirator works ,which is an application of Bernoulli's principle?????

Discussion

4181.	50.Which has greater size CS+ & F-
Answer» 50.Which has greater size CS+ & F-

Discussion

4182.	A point object is moving with velocity v0=10^i m/s along x-axis as shown in figure. Relative velocity of its image in mirror M1 with respect to mirror image velocity in M2 is : (Take sin 37∘=0.6)
Answer» A point object is moving with velocity $v_{0} = 10^i m / s$ along x-axis as shown in figure. Relative velocity of its image in mirror $M_{1}$ with respect to mirror image velocity in $M_{2}$ is : (Take $sin 37^{\circ} = 0.6$ )

4182.

A point object is moving with velocity v0=10^i m/s along x-axis as shown in figure. Relative velocity of its image in mirror M1 with respect to mirror image velocity in M2 is : (Take sin 37∘=0.6)

Answer»

A point object is moving with velocity $v_{0} = 10^i m / s$ along x-axis as shown in figure. Relative velocity of its image in mirror $M_{1}$ with respect to mirror image velocity in $M_{2}$ is :

(Take $sin 37^{\circ} = 0.6$ )

Discussion

4183.	Figure given below shows a uniform disc of radius 8 units. A hole of radius 4 units has been cut out from left of its centre and is placed on the right of the centre of the disc. Find the COM of the resulting shape.
Answer» Figure given below shows a uniform disc of radius $8$ units. A hole of radius $4$ units has been cut out from left of its centre and is placed on the right of the centre of the disc. Find the $C O M$ of the resulting shape.

Discussion

4184.	A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms−1. If the mass of each stone is 0.05 kg. What is the mass of the disc?(g=10 ms−2)
Answer» A solid disc of mass $M$ is just held in air horizontal by throwing $40$ stones per sec vertically upwards to strike the disc each with a velocity $6$ $m s^{- 1}$ . If the mass of each stone is $0.05$ kg. What is the mass of the disc? $(g = 10 m s^{- 2})$

Discussion

4185.	a particle is dropped from a ballon rising at 20 m/s at a time when the ballon is 80 m above the ground.if g=10m/s then the particle reaches the groun approximately is?
Answer» a particle is dropped from a ballon rising at 20 m/s at a time when the ballon is 80 m above the ground.if g=10m/s then the particle reaches the groun approximately is?

Discussion

4186.	graph between displacement and velocity in shm is
Answer» graph between displacement and velocity in shm is

Discussion

4187.	5. A ball of mass 100 g is suspended by a string 40 cmlong. Keeping the string taut, the ball describes ahorizontal circle of radius 10 cm. Find the angular
Answer» 5. A ball of mass 100 g is suspended by a string 40 cmlong. Keeping the string taut, the ball describes ahorizontal circle of radius 10 cm. Find the angular

Discussion

4188.	y(t) is the response of an LTI system whose x(t) and h(t) are shown then the value of y(0)+y(1) is ____8
Answer» $y (t)$ is the response of an LTI system whose x(t) and h(t) are shown then the value of y(0)+y(1) is ____ 8

Discussion

4189.	A plane electromagnetic wave, propagating in space, has an electric field of amplitude 9×103 V/m. The amplitude of the magnetic field is,
Answer» A plane electromagnetic wave, propagating in space, has an electric field of amplitude $9 \times 10^{3} V/m$ . The amplitude of the magnetic field is,

Discussion

4190.	The ratio of the intensity at the centre of a bright fringe to the intensity at a point one- quarter of the fringe width from the centre is
Answer» The ratio of the intensity at the centre of a bright fringe to the intensity at a point one- quarter of the fringe width from the centre is

Discussion

4191.	why dipole induced dipole attraction force is greater than london dispersion forc
Answer» why dipole induced dipole attraction force is greater than london dispersion forc

Discussion

4192.	The potential energy of a simple harmonic oscillator when the particle is half way to its end point is: (where E is the total energy)
Answer» The potential energy of a simple harmonic oscillator when the particle is half way to its end point is: (where E is the total energy)

Discussion

4193.	A man of mass 75 kg is standing on a platform of mass 15 kg kept on a smooth horizontal surface. The man starts moving on the platform with a velocity of 20 m/s relative to the platform. Then, magnitude of the recoil velocity of the platform is
Answer» A man of mass $75 kg$ is standing on a platform of mass $15 kg$ kept on a smooth horizontal surface. The man starts moving on the platform with a velocity of $20 m/s$ relative to the platform. Then, magnitude of the recoil velocity of the platform is

Discussion

4194.	A parallel plate capacitor has two layers of dielectric as shown in figure. This capacitor is connected across a battery, then the ratio of potential difference across the dielectric layers is:
Answer» A parallel plate capacitor has two layers of dielectric as shown in figure. This capacitor is connected across a battery, then the ratio of potential difference across the dielectric layers is:

Discussion

4195.	A highly conducting solid sphere of radius R , density ρ and specific heat s is kept in an evacuated chamber. A parallel beam of thermal radiation of intensity I is incident on its surface.Consider the sphere to be a perfectly black body and its temperature at certain instant t=0 is considered as T0 [Take Stefan's constant as σ]The maximum attainable temperature of the sphere is
Answer» A highly conducting solid sphere of radius $R$ , density $ρ$ and specific heat $s$ is kept in an evacuated chamber. A parallel beam of thermal radiation of intensity $I$ is incident on its surface. Consider the sphere to be a perfectly black body and its temperature at certain instant $t = 0$ is considered as $T_{0}$ [Take Stefan's constant as $σ$ ] The maximum attainable temperature of the sphere is

Discussion

4196.	The density of a material in SI units is 128 kg m−3. In certain units in which the unit of length is 25 cm and the unit of mass is 50 g, the numerical value of density of the material is
Answer» The density of a material in SI units is $128 {kg m}^{- 3}$ . In certain units in which the unit of length is $25 cm$ and the unit of mass is $50 g$ , the numerical value of density of the material is

Discussion

4197.	The r.m.s speed of hydrogen molecules at room temperature is 2400 m/s. At room temperature, the r.m.s. speed of oxygen molecules would be
Answer» The r.m.s speed of hydrogen molecules at room temperature is 2400 m/s. At room temperature, the r.m.s. speed of oxygen molecules would be

Discussion

4198.	Two stones each of mass 5kg fall on a wheel from a height of 10m. The wheel stirs 2kg water. The rise in temperature of water would be
Answer» Two stones each of mass 5kg fall on a wheel from a height of 10m. The wheel stirs 2kg water. The rise in temperature of water would be

Discussion

4199.	A weight of 100 N is suspended by two wires made of steel and copper as shown in the figure. Length of steel wire is 1 m and copper wire is √3 m. Find the ratio of change in length of copper wire (Δlc) to change in length of steel wire (Δls). Given Young's modulus: Ysteel=2×1011 N/m2, Ycopper=1×1011 N/m2
Answer» A weight of $100 N$ is suspended by two wires made of steel and copper as shown in the figure. Length of steel wire is $1 m$ and copper wire is $\sqrt{3} m$ . Find the ratio of change in length of copper wire $(Δ l_{c})$ to change in length of steel wire $(Δ l_{s})$ . Given Young's modulus: $Y_{s t e e l} = 2 \times 10^{11} N / m^{2}$ , $Y_{c o p p e r} = 1 \times 10^{11} N / m^{2}$

Discussion

4200.	Find the second orderderivatives of the function.
Answer» Find the second order derivatives of the function.

4200.

Find the second orderderivatives of the function.

Answer»

Find the second order
derivatives of the function.

Discussion

Explore topic-wise InterviewSolutions in .

A body of mass 1 kg rests on a horizontal floor with which it has a coefficient of static friction1√3. It is desired to make the body move by applying the minimum possible force F N. The value of F will be . (Round off to the Nearest Integer)[Take g =10 ms2]

Suppose the initial charge on the capacitor in Exercise 7.7 is 6 mC.What is the total energy stored in the circuit initially? What is the total energy at later time?

The ratio to radii of curvature of a biconvex lens R1:R2 = 2 : 3. Its refractive index and focal length is 1.5 and 12 cm respectively. What is the value of R1? Consider R1 and R2 are positive and negative respectively.

There is a shell of mass M, outer radius 2R and inner radius R. If gravitational field due to M4 (shaded part) at center of shell is →g, then field due to remaining part at center is

Which electric field is responsible for the proton’s trajectory as shown below?

25. For head-on collision between two colliding balls ofequal radii r, the impact parameter is equal to(1) 2r(2) Zero(3) More than 2r(4) Less than 2r

6.The water drops are falling at regular intervals from the tap which is h m about the ground. the III drop is about to leave the tap when first drop touches the ground if the distance between the second drop and first drop is 3. 75 m then what is the height h ?

Define vector 0 and give two examples.

What is wavelength intensity relationship?

41. There are two charges +2uC and -3uC.the ratio of forces acting on them will be

Two radioactive samples 1 and 2 have half lives T1 and T2 (T1&gt;T2) respectively. At t=0, the activity of 2 was twice the activity of 1. Their activity will become equal after a time

A quantity X is defined as the ratio of the angular to linear momentum of an object. Then the dimensions of X are -

A bob of a simple pendulum of mass m is projected horizontally with some speed from its lowest point such that the string will slack at a position where it makes an angle 60∘ with the upward vertical direction. Find the tension in the string at the lowest position.

In figure (a square), identify the following vectors: (i) Equal

moment of inertia of trinagular lamina along its vertex , centroid, and bas

1) When will a concave lens behave like convex lens? 2) When will a convex lens behave like a concave lens?

A block of mass 2 kg moving with speed 5 m/s collides with another block of mass 4 kg at rest. The lighter block comes to rest after the collision. Find the coefficient of restitution (e). (Neglect all other external force)

53.What is centre of gravity and equilibrium and it's types define them

13. 80gm SO2 react with 40gm O2. Identify limiting reagent ??

How can wave theory explain Rectilinear Propogation of Light?

For the following logic gates circuit, what is the correct expression for its output?

A falling stone takes 0.2 sec to fall across a windowwhich is 1m high. From how far above the top of thewindow was the stone dr opped

A stone dropped from the top of a tower is found to travel 5/9 of the height of the tower during the last second of its fall. The time of fall will be ? 1) 2sec 2) 3 sec 3) 4 sec 4) 5 sec

If ∫(2x+3)dxx(x+1)(x+2)(x+3)+1=K−1f(x) where f(x) is of the form of ax2+bx+c and K is the constant of integration, then (a+b+c) equals

A photon detector receives a total of 3.15 X 10^-8 J from the radiation of 600 nm. Calculate the number of photons received

Question 29Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?

How does an aspirator works ,which is an application of Bernoulli's principle?????

50.Which has greater size CS+ & F-

A point object is moving with velocity v0=10^i m/s along x-axis as shown in figure. Relative velocity of its image in mirror M1 with respect to mirror image velocity in M2 is : (Take sin 37∘=0.6)

Figure given below shows a uniform disc of radius 8 units. A hole of radius 4 units has been cut out from left of its centre and is placed on the right of the centre of the disc. Find the COM of the resulting shape.

A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms−1. If the mass of each stone is 0.05 kg. What is the mass of the disc?(g=10 ms−2)

a particle is dropped from a ballon rising at 20 m/s at a time when the ballon is 80 m above the ground.if g=10m/s then the particle reaches the groun approximately is?

graph between displacement and velocity in shm is

5. A ball of mass 100 g is suspended by a string 40 cmlong. Keeping the string taut, the ball describes ahorizontal circle of radius 10 cm. Find the angular

y(t) is the response of an LTI system whose x(t) and h(t) are shown then the value of y(0)+y(1) is ____8

A plane electromagnetic wave, propagating in space, has an electric field of amplitude 9×103 V/m. The amplitude of the magnetic field is,

The ratio of the intensity at the centre of a bright fringe to the intensity at a point one- quarter of the fringe width from the centre is

why dipole induced dipole attraction force is greater than london dispersion forc

The potential energy of a simple harmonic oscillator when the particle is half way to its end point is: (where E is the total energy)

A man of mass 75 kg is standing on a platform of mass 15 kg kept on a smooth horizontal surface. The man starts moving on the platform with a velocity of 20 m/s relative to the platform. Then, magnitude of the recoil velocity of the platform is

A parallel plate capacitor has two layers of dielectric as shown in figure. This capacitor is connected across a battery, then the ratio of potential difference across the dielectric layers is:

The density of a material in SI units is 128 kg m−3. In certain units in which the unit of length is 25 cm and the unit of mass is 50 g, the numerical value of density of the material is

The r.m.s speed of hydrogen molecules at room temperature is 2400 m/s. At room temperature, the r.m.s. speed of oxygen molecules would be

Two stones each of mass 5kg fall on a wheel from a height of 10m. The wheel stirs 2kg water. The rise in temperature of water would be

Find the second orderderivatives of the function.

Two radioactive samples 1 and 2 have half lives T1 and T2 (T1>T2) respectively. At t=0, the activity of 2 was twice the activity of 1. Their activity will become equal after a time