50278 + Interview Questions in Physics

1.	ParagraphA frame of reference that is accelerated with respect to an inertial frame of reference is called a non-inertial frame of reference. A coordinate system fixed on a circular disc rotating about a fixed axis with a constant angular velocity ω is an example of a non-inertial frame of reference. The relationship between the force →Frot experience by a particle of mass m moving on the rotating disc and the force →Fin experienced by the particle in an inertial frame of reference is→Frot=→Fin+2m(→vrot×→ω)+m(→ω×→r)×→ω,where →vrot is the velocity of the particle in the rotating frame of reference and →r is the position vector of the particle with respect to the centre of the disc. Now consider a smooth slot along a diameter of a disc of radius R rotating counterclockwise with a constant angular speed ω about its vertical axis through its center. We assign a coordinate system with the origin at the center of the disc, the x−axis along the slot, the y− axis perpendicular to the slot and the z− axis along the rotation axis →ω=ω→k. A small block of mass m is gently placed in the slot at →r=(R/2)→i at t=0 and is constrained to move only along the slot.The net reaction of the disc on the block is
Answer» Paragraph A frame of reference that is accelerated with respect to an inertial frame of reference is called a non-inertial frame of reference. A coordinate system fixed on a circular disc rotating about a fixed axis with a constant angular velocity $ω$ is an example of a non-inertial frame of reference. The relationship between the force ${\to F}_{rot}$ experience by a particle of mass $m$ moving on the rotating disc and the force ${\to F}_{in}$ experienced by the particle in an inertial frame of reference is ${\to F}_{rot} = {\to F}_{in} + 2 m ({\to v}_{rot} \times \to ω) + m (\to ω \times \to r) \times \to ω,$ where ${\to v}_{rot}$ is the velocity of the particle in the rotating frame of reference and $\to r$ is the position vector of the particle with respect to the centre of the disc. Now consider a smooth slot along a diameter of a disc of radius $R$ rotating counterclockwise with a constant angular speed $ω$ about its vertical axis through its center. We assign a coordinate system with the origin at the center of the disc, the $x -$ axis along the slot, the $y -$ axis perpendicular to the slot and the $z -$ axis along the rotation axis $\to ω = ω \to k$ . A small block of mass $m$ is gently placed in the slot at $\to r = (R / 2) \to i$ at $t = 0$ and is constrained to move only along the slot. The net reaction of the disc on the block is

Discussion

2.	A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to F1 on a particle placed at a distance 3R from the centre of the sphere. A spherical cavity of radius R2 is now made in the sphere as shown in the figure. The sphere with cavity now applies a gravitational force F2 on the same particle. The ratio F2F1 is:
Answer» A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to $F_{1}$ on a particle placed at a distance 3R from the centre of the sphere. A spherical cavity of radius $\frac{R}{2}$ is now made in the sphere as shown in the figure. The sphere with cavity now applies a gravitational force $F_{2}$ on the same particle. The ratio $\frac{F_{2}}{F_{1}}$ is:

Discussion

3.	A point charge Q(=3×10−12C) rotates uniformly in a vertical circle of radius R = 1 mm. The axis of the circle is aligned along the magnetic axis of the earth. At what value of the angular speed ω, the effective magnetic field at the center of the circle will be reduced to zero? (Horizontal component of Earth’s magnetic field is 30 micro Tesla)
Answer» A point charge $Q (= 3 \times 10^{- 12} C)$ rotates uniformly in a vertical circle of radius R = 1 mm. The axis of the circle is aligned along the magnetic axis of the earth. At what value of the angular speed $ω$ , the effective magnetic field at the center of the circle will be reduced to zero? (Horizontal component of Earth’s magnetic field is 30 micro Tesla)

Discussion

4.	Two parallel wires PQ and RS are connected by a capacitor and a metal rod CD and placed in a magnetic field directed into the page as shown in figure. If rod CD is moved with a velocity υ as shown in the figure,
Answer» Two parallel wires PQ and RS are connected by a capacitor and a metal rod CD and placed in a magnetic field directed into the page as shown in figure. If rod CD is moved with a velocity υ as shown in the figure,

Discussion

5.	A uniform wire of length l = 800 m and cross-sectional area s=1mm2 is made of a material of density P=8×103kg/m3 and young's modulus Y=2×1011N/m2. Wire is placed on a frictionless horizontal surface and an end is pulled by a constant horizontal force( F = 1 N) then extention in front half of wire in mm is (Write upto two digits after the decimal point.)
Answer» A uniform wire of length l = 800 m and cross-sectional area $s = 1 m m^{2}$ is made of a material of density $P = 8 \times 10^{3} k g / m^{3}$ and young's modulus $Y = 2 \times 10^{11} N / m^{2}$ . Wire is placed on a frictionless horizontal surface and an end is pulled by a constant horizontal force( F = 1 N) then extention in front half of wire in mm is (Write upto two digits after the decimal point.)

Discussion

6.	Three rods of material x and two rods of material y are connected as shown in figure. All the rods are of identical length and cross - sectional area. The end A is maintained at 100∘C and the junction C at 0∘C. It is given that resistance of rod of material x is R. Further, Kx = 2Ky . Match the entries of column I and column II column1column2A.Temperature of junction BP.Does not behave like a balanced wheatstones′s bridgeB.Temperature of junction CQ.Is twice of the otherC.This network isR.4007∘CD.Resistance of rod of material yS.3007∘C
Answer» Three rods of material x and two rods of material y are connected as shown in figure. All the rods are of identical length and cross - sectional area. The end A is maintained at 100 $^{\circ}$ C and the junction C at 0 $^{\circ}$ C. It is given that resistance of rod of material x is R. Further, $K_{x}$ = ${2 K}_{y}$ . Match the entries of column I and column II $\begin{matrix} c o l u m n 1 & c o l u m n 2 A . T e m p e r a t u r e o f j u n c t i o n B & P . D o e s n o t b e h a v e l i k e a b a l a n c e d w h e a t s t o n e s^{'} s b r i d g e B . T e m p e r a t u r e o f j u n c t i o n C & Q . I s t w i c e o f t h e o t h e r C . T h i s n e t w o r k i s & R . {\frac{400}{7}}^{\circ} C D . R e s i s t a n c e o f r o d o f m a t e r i a l y & S . {\frac{300}{7}}^{\circ} C \end{matrix}$

6.

Three rods of material x and two rods of material y are connected as shown in figure. All the rods are of identical length and cross - sectional area. The end A is maintained at 100∘C and the junction C at 0∘C. It is given that resistance of rod of material x is R. Further, Kx = 2Ky . Match the entries of column I and column II column1column2A.Temperature of junction BP.Does not behave like a balanced wheatstones′s bridgeB.Temperature of junction CQ.Is twice of the otherC.This network isR.4007∘CD.Resistance of rod of material yS.3007∘C

Answer»

Three rods of material x and two rods of material y are connected as shown in figure. All the rods are of identical length and cross - sectional area. The end A is maintained at 100 $^{\circ}$ C and the junction C at 0 $^{\circ}$ C. It is given that resistance of rod of material x is R. Further, $K_{x}$ = ${2 K}_{y}$ .

Match the entries of column I and column II

$\begin{matrix} c o l u m n 1 & c o l u m n 2 A . T e m p e r a t u r e o f j u n c t i o n B & P . D o e s n o t b e h a v e l i k e a b a l a n c e d w h e a t s t o n e s^{'} s b r i d g e B . T e m p e r a t u r e o f j u n c t i o n C & Q . I s t w i c e o f t h e o t h e r C . T h i s n e t w o r k i s & R . {\frac{400}{7}}^{\circ} C D . R e s i s t a n c e o f r o d o f m a t e r i a l y & S . {\frac{300}{7}}^{\circ} C \end{matrix}$

Discussion

7.	A conductor of length l is rotating with constant angular velocity ω about an axis OO′ in a uniform magnetic field B as shown in figure. The emf induced between ends P and Q will be
Answer» A conductor of length $l$ is rotating with constant angular velocity $ω$ about an axis $O O^{'}$ in a uniform magnetic field $B$ as shown in figure. The emf induced between ends $P$ and $Q$ will be

Discussion

8.	A point charge Q is located at the centre of a cube of edge length a. The total electric flux through one of the face of the cube is
Answer» A point charge $Q$ is located at the centre of a cube of edge length $a$ . The total electric flux through one of the face of the cube is

Discussion

9.	A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 43 and the fish is 12 cm below the surface. The radius of this circle is
Answer» A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is $\frac{4}{3}$ and the fish is 12 cm below the surface. The radius of this circle is

Discussion

10.	A water drop is divided into eight equal droplets. The pressure difference between inner and outer sides of the big drop
Answer» A water drop is divided into eight equal droplets. The pressure difference between inner and outer sides of the big drop

Discussion

11.	Light of wavelength 2475Å is incident on barium. Photoelectrons emitted described a circle of radius 100 cm in a magnetic field of magnitude 1√17×10−5 Tesla. Work function of the barium is ( Given: em = 1.7×1011 Ckg−1
Answer» Light of wavelength 2475 $Å$ is incident on barium. Photoelectrons emitted described a circle of radius 100 $c m$ in a magnetic field of magnitude $\frac{1}{\sqrt{17}} \times 10^{- 5}$ Tesla. Work function of the barium is ( Given: $\frac{e}{m} = 1.7 \times 10^{11} C k g^{- 1}$

Discussion

12.	There is a constant homogeneous electric field of 100 Vm–1 within the region x=0 and x=0.167 m pointing in the positive x−direction. There is a constant homogeneous magnetic field B within the region x=0.167 m and x=0.334 m pointing in the z−direction. A proton (at rest) at the origin (x=0,y=0) is released in the positive x−direction. The minimum strength of the magnetic field B(in mT), so that the proton will reach x=0,y=0.167 m is (mass of the proton =1.67×10–27 kg)
Answer» There is a constant homogeneous electric field of $100 {Vm}^{- 1}$ within the region $x = 0$ and $x = 0.167 m$ pointing in the positive $x -$ direction. There is a constant homogeneous magnetic field $B$ within the region $x = 0.167 m$ and $x = 0.334 m$ pointing in the $z -$ direction. A proton (at rest) at the origin $(x = 0, y = 0)$ is released in the positive $x -$ direction. The minimum strength of the magnetic field $B$ (in $m T$ ), so that the proton will reach $x = 0, y = 0.167 m$ is (mass of the proton $= 1.67 \times 10^{- 27} kg$ )

Discussion

13.	Spacing between two successive nodes in a standing wave on a string is x. If tension in the string is doubled keeping frequency constant, then find the new spacing between successive nodes.
Answer» Spacing between two successive nodes in a standing wave on a string is $x$ . If tension in the string is doubled keeping frequency constant, then find the new spacing between successive nodes.

Discussion

14.	From the circular disk of radius 4R, two small discs of radius R each are cut off. If R=14 cm, then find the location of the center of mass of the new structure (in cm). (Take O to be the origin)
Answer» From the circular disk of radius $4 R$ , two small discs of radius $R$ each are cut off. If $R = 14 cm$ , then find the location of the center of mass of the new structure (in $cm)$ . (Take $O$ to be the origin)

Discussion

15.	A glass marble whose mass is 200 g, falls from a height of 2.5 m and rebounds to a height of 1.6 m. Find the impulse acting due to its fall
Answer» A glass marble whose mass is $200 g$ , falls from a height of $2.5 m$ and rebounds to a height of $1.6 m$ . Find the impulse acting due to its fall

Discussion

16.	A plane electromagnetic wave of frequency 40 MHz travels in free space in the X - direction. At some point and at some instant, the electric field →E has its maximum value of 750 N/C in Y -direction. The wavelength of the wave is-
Answer» A plane electromagnetic wave of frequency $40 MHz$ travels in free space in the X - direction. At some point and at some instant, the electric field $\to E$ has its maximum value of $750 N/C$ in Y -direction. The wavelength of the wave is-

Discussion

17.	The height at which the acceleration due to gravity becomes g9 (where g = the acceleration due to gravity on the surface of th earth) in terms of R, radius of the earth is
Answer» The height at which the acceleration due to gravity becomes $\frac{g}{9}$ (where g = the acceleration due to gravity on the surface of th earth) in terms of $R$ , radius of the earth is

Discussion

18.	A small solid sphere of radius r rolls down an incline without slipping which ends into a vertical loop of radius R. Find the height above the base so that it just loops the loop.
Answer» A small solid sphere of radius $r$ rolls down an incline without slipping which ends into a vertical loop of radius $R$ . Find the height above the base so that it just loops the loop.

Discussion

19.	Suresh and Shyam of masses 60 kg and 70 kg respectively are standing at the two extremes of a long boat of mass 50 kg and length 6 m standing still in water. After some time, they come to the middle of the boat. Neglecting water resistance, how far does the boat move on the water during the process?
Answer» Suresh and Shyam of masses $60 kg$ and $70 kg$ respectively are standing at the two extremes of a long boat of mass $50 kg$ and length $6 m$ standing still in water. After some time, they come to the middle of the boat. Neglecting water resistance, how far does the boat move on the water during the process?

Discussion

20.	The equation of state for a gas is given by PV=nRT+αV, where n is the number of moles and α is a positive constant. The initial pressure and temperature of 1 mole of the gas contained in a cylinder are P0 and T0 respectively. The work done by the gas when its temperature doubles isobarically is
Answer» The equation of state for a gas is given by $P V = n R T + α V$ , where $n$ is the number of moles and $α$ is a positive constant. The initial pressure and temperature of 1 mole of the gas contained in a cylinder are $P_{0}$ and $T_{0}$ respectively. The work done by the gas when its temperature doubles isobarically is

Discussion

21.	A point charge +10μC is at a distance 5cm directly above the centre of a square of side 10cm, as shown in figure. What is the magnitude of the electric flux through the square?
Answer» A point charge $+ 10 μ C$ is at a distance 5cm directly above the centre of a square of side 10cm, as shown in figure. What is the magnitude of the electric flux through the square?

Discussion

22.	At a given instant, block A is moving upwards with velocity of 5 m/s. What will be velocity of block B at that instant ? (Take upward velocity to be positive.)
Answer» At a given instant, block A is moving upwards with velocity of $5 m / s$ . What will be velocity of block B at that instant ? (Take upward velocity to be positive.)

Discussion

23.	Water flows steadily through a horizontal pipe of a variable cross-section. If the pressure of water is p at a point where the velocity of flow is v, what is the pressure at another point where the velocity of flow is 2v, ρ being the density of water?
Answer» Water flows steadily through a horizontal pipe of a variable cross-section. If the pressure of water is $p$ at a point where the velocity of flow is $v$ , what is the pressure at another point where the velocity of flow is $2 v, ρ$ being the density of water?

Discussion

24.	The value of mass m for which the 100 kg block remains in static equillibrium is/are: (take g=10 m/s2)
Answer» The value of mass $m$ for which the $100 k g$ block remains in static equillibrium is/are: (take $g = 10 {m / s}^{2}$ )

Discussion

25.	Two positive ions, each carrying a charge q, are separated by a distance d, repulsion between the ions, the number of electrons missing from each ion will be:
Answer» Two positive ions, each carrying a charge q, are separated by a distance d, repulsion between the ions, the number of electrons missing from each ion will be:

Discussion

26.	Two cubical blocks identical in dimensions float in water in such a way that the first block floats with half part immersed in water and the second block floats with 3/4 th of its volume immersed inside the water. The ratio of density of first block to that of second block is
Answer» Two cubical blocks identical in dimensions float in water in such a way that the first block floats with half part immersed in water and the second block floats with $3 / 4 th$ of its volume immersed inside the water. The ratio of density of first block to that of second block is

Discussion

27.	A motorboat covers a given distance in 6 hours moving downstream in a river. It covers the same distance in 10 hours moving upstream. The time taken to cover the same distance in still water is
Answer» A motorboat covers a given distance in $6 hours$ moving downstream in a river. It covers the same distance in $10 hours$ moving upstream. The time taken to cover the same distance in still water is

Discussion

28.	A particle of mass m is moving with constant velocity v parallel to x-axis in x-y plane as shown in figure. Calculate its angular momentum with respect to origin at anyinstant 't'.
Answer» A particle of mass m is moving with constant velocity v parallel to x-axis in x-y plane as shown in figure. Calculate its angular momentum with respect to origin at anyinstant 't'.

28.

A particle of mass m is moving with constant velocity v parallel to x-axis in x-y plane as shown in figure. Calculate its angular momentum with respect to origin at anyinstant 't'.

Answer»

A particle of mass m is moving with constant velocity v parallel to x-axis in x-y plane as shown in figure. Calculate its angular momentum with respect to origin at anyinstant 't'.

Discussion

29.	If a displacement vector of AB is ^i+^j+2^k and point A having a position vector 2^i+5^j+6^k, then find the position vector of B ?
Answer» If a displacement vector of $A B$ is $^i +^j + 2^k$ and point $A$ having a position vector $2^i + 5^j + 6^k$ , then find the position vector of $B$ ?

Discussion

30.	A force of 15 N displaces a box on a horizontal surface through a distance of 10 m. Calculate the angle which the force makes with the direction of motion of the body, if work done is 75 J.
Answer» A force of $15 N$ displaces a box on a horizontal surface through a distance of $10 m$ . Calculate the angle which the force makes with the direction of motion of the body, if work done is $75 J$ .

Discussion

31.	A showman comes running and stands at the centre of the rotating platform.Considering the platform and the showman a system,which of the following is conserved? 1. Linear momentum 2. Angular momentum 3.kinetice energy 4. None of the above
Answer» A showman comes running and stands at the centre of the rotating platform.Considering the platform and the showman a system,which of the following is conserved? 1. Linear momentum 2. Angular momentum 3.kinetice energy 4. None of the above

31.

A showman comes running and stands at the centre of the rotating platform.Considering the platform and the showman a system,which of the following is conserved? 1. Linear momentum 2. Angular momentum 3.kinetice energy 4. None of the above

Answer»

A showman comes running and stands at the centre of the rotating platform.Considering the platform and the showman a system,which of the following is conserved?

1. Linear momentum

2. Angular momentum

3.kinetice energy

4. None of the above

Discussion

32.	Why is radium used for therapy of cancer instead it was the reason of Pierre curie's death due to exposure of radium for a long time?
Answer» Why is radium used for therapy of cancer instead it was the reason of Pierre curie's death due to exposure of radium for a long time?

Discussion

33.	When 2g of a gas A is introduced into an evacuated flask kept at 250 C, the pressure is found to be 1 atmosphere. If 3g of another gas is then added to the same flask, the total pressure becomes 1.5 atm. Assuming ideal behaviour, the ratio of their molecular weights MA : MB is
Answer» When 2g of a gas A is introduced into an evacuated flask kept at $25^{0} C$ , the pressure is found to be 1 atmosphere. If 3g of another gas is then added to the same flask, the total pressure becomes 1.5 atm. Assuming ideal behaviour, the ratio of their molecular weights $M_{A} : M_{B}$ is

Discussion

34.	Can satellite revolving around the earth be taken as simple harmonic motion?(give clear explanation)
Answer» Can satellite revolving around the earth be taken as simple harmonic motion?(give clear explanation)

Discussion

35.	Three rods of the same mass are placed as shown in the figure. The co-ordinates of the centre of mass of the system is
Answer» Three rods of the same mass are placed as shown in the figure. The co-ordinates of the centre of mass of the system is

Discussion

36.	We say that the universe is constantly expanding. The area of the universe was certain in the past. In which area is the universe expanding
Answer» We say that the universe is constantly expanding. The area of the universe was certain in the past. In which area is the universe expanding

Discussion

37.	A body is being moved along a straight line by a machine delivering a constant power. The distance covered by the body in time t is proportional to
Answer» A body is being moved along a straight line by a machine delivering a constant power. The distance covered by the body in time t is proportional to

Discussion

38.	A 10 kg weight is raused to a height of 2 m wth an acceleration of 1.5 m/sec square .compute the work done if g = 10 m/sec square
Answer» A 10 kg weight is raused to a height of 2 m wth an acceleration of 1.5 m/sec square .compute the work done if g = 10 m/sec square

Discussion

39.	The energy of a photon is 3 × 10−12 ergs. What is its wavelength in nm ? (h = 6.62 × 10−27 erg.Sec; c = 3 × 1010cm.s−1)
Answer» The energy of a photon is $3 \times 10^{- 12} e r g s$ . What is its wavelength in nm ? ( $h$ = $6.62 \times 10^{- 27} e r g . S e c$ ; $c$ = $3 \times 10^{10} c m . s^{- 1})$

Discussion

40.	The magnetic field due to a current carrying circular loop of radius 3 cm at a point on its axis at a distance of 4 cm from the centre is 54 μT. The magnetic field (in μT) at the centre of the loop will be
Answer» The magnetic field due to a current carrying circular loop of radius 3 cm at a point on its axis at a distance of 4 cm from the centre is 54 $μ$ T. The magnetic field (in $μ$ T) at the centre of the loop will be

Discussion

41.	For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery Is this above statement true. ??
Answer» For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery Is this above statement true. ??

41.

For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery Is this above statement true. ??

Answer»

For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery

Is this above statement true. ??

Discussion

42.	How is resonance frequency related to a radio or how is a quality factor affect the radio ?
Answer» How is resonance frequency related to a radio or how is a quality factor affect the radio ?

Discussion

43.	Why the value of g is more at the poles than at the equator of the earth?
Answer» Why the value of g is more at the poles than at the equator of the earth?

Discussion

44.	An ant moves from A to B and then comes back to point A and reaches C. Find the distance (d) and displacement (s) of the ant in this entire journey.
Answer» An ant moves from A to B and then comes back to point A and reaches C. Find the distance (d) and displacement (s) of the ant in this entire journey.

44.

An ant moves from A to B and then comes back to point A and reaches C. Find the distance (d) and displacement (s) of the ant in this entire journey.

Answer»

An ant moves from A to B and then comes back to point A and reaches C. Find the distance (d) and displacement (s) of the ant in this entire journey.

Discussion

45.	At what temperature the RMS velocity of SO2 be same as that of O2 at 303 K
Answer» At what temperature the RMS velocity of SO2 be same as that of O2 at 303 K

45.

At what temperature the RMS velocity of SO2 be same as that of O2 at 303 K

Answer»

At what temperature the RMS velocity of SO2 be same as that of O2 at 303 K

Discussion

46.	Which of the following is called a fictitious force?
Answer» Which of the following is called a fictitious force?

Discussion

47.	Referring to a - x graph, find the velocity when the displacement of the particle is 100 m. assume initial velocity as zero.
Answer» Referring to a - x graph, find the velocity when the displacement of the particle is 100 m. assume initial velocity as zero.

47.

Referring to a - x graph, find the velocity when the displacement of the particle is 100 m. assume initial velocity as zero.

Answer»

Referring to a - x graph, find the velocity when the displacement of the particle is 100 m. assume initial velocity as zero.

Discussion

48.	The equation y = 0.15 sin 5 x cos 300 t , describes a stationary wave. The wavelength of the stationary wave is [MP PMT 1995]
Answer» The equation y = 0.15 sin 5 x cos 300 t , describes a stationary wave. The wavelength of the stationary wave is [MP PMT 1995]

48.

The equation y = 0.15 sin 5 x cos 300 t , describes a stationary wave. The wavelength of the stationary wave is [MP PMT 1995]

Answer»

The equation y = 0.15 sin 5 x cos 300 t , describes a stationary wave. The

wavelength of the stationary wave is

[MP PMT 1995]

Discussion

49.	What dose a polaroid consist of? Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why
Answer» What dose a polaroid consist of? Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why

Discussion

50.	A particle moves in the x-y plane under the action of a force →F=−2k sin kt(^i+^j) at any time t its linear momentum is given by Px=2cos(kt)andPy=2cos(kt) The angle between →F and→P at time t is
Answer» A particle moves in the x-y plane under the action of a force $\to F = - 2 k s i n k t (^i +^j)$ at any time t its linear momentum is given by $P_{x} = 2 c o s (k t) a n d P_{y} = 2 c o s (k t)$ The angle between $\to F a n d \to P$ at time t is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Two parallel wires PQ and RS are connected by a capacitor and a metal rod CD and placed in a magnetic field directed into the page as shown in figure. If rod CD is moved with a velocity υ as shown in the figure,

A conductor of length l is rotating with constant angular velocity ω about an axis OO′ in a uniform magnetic field B as shown in figure. The emf induced between ends P and Q will be

A point charge Q is located at the centre of a cube of edge length a. The total electric flux through one of the face of the cube is

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 43 and the fish is 12 cm below the surface. The radius of this circle is

A water drop is divided into eight equal droplets. The pressure difference between inner and outer sides of the big drop

Light of wavelength 2475Å is incident on barium. Photoelectrons emitted described a circle of radius 100 cm in a magnetic field of magnitude 1√17×10−5 Tesla. Work function of the barium is ( Given: em = 1.7×1011 Ckg−1

Spacing between two successive nodes in a standing wave on a string is x. If tension in the string is doubled keeping frequency constant, then find the new spacing between successive nodes.

From the circular disk of radius 4R, two small discs of radius R each are cut off. If R=14 cm, then find the location of the center of mass of the new structure (in cm). (Take O to be the origin)

A glass marble whose mass is 200 g, falls from a height of 2.5 m and rebounds to a height of 1.6 m. Find the impulse acting due to its fall

A plane electromagnetic wave of frequency 40 MHz travels in free space in the X - direction. At some point and at some instant, the electric field →E has its maximum value of 750 N/C in Y -direction. The wavelength of the wave is-

The height at which the acceleration due to gravity becomes g9 (where g = the acceleration due to gravity on the surface of th earth) in terms of R, radius of the earth is

A small solid sphere of radius r rolls down an incline without slipping which ends into a vertical loop of radius R. Find the height above the base so that it just loops the loop.

The equation of state for a gas is given by PV=nRT+αV, where n is the number of moles and α is a positive constant. The initial pressure and temperature of 1 mole of the gas contained in a cylinder are P0 and T0 respectively. The work done by the gas when its temperature doubles isobarically is

A point charge +10μC is at a distance 5cm directly above the centre of a square of side 10cm, as shown in figure. What is the magnitude of the electric flux through the square?

At a given instant, block A is moving upwards with velocity of 5 m/s. What will be velocity of block B at that instant ? (Take upward velocity to be positive.)

Water flows steadily through a horizontal pipe of a variable cross-section. If the pressure of water is p at a point where the velocity of flow is v, what is the pressure at another point where the velocity of flow is 2v, ρ being the density of water?

The value of mass m for which the 100 kg block remains in static equillibrium is/are: (take g=10 m/s2)

Two positive ions, each carrying a charge q, are separated by a distance d, repulsion between the ions, the number of electrons missing from each ion will be:

Two cubical blocks identical in dimensions float in water in such a way that the first block floats with half part immersed in water and the second block floats with 3/4 th of its volume immersed inside the water. The ratio of density of first block to that of second block is

A motorboat covers a given distance in 6 hours moving downstream in a river. It covers the same distance in 10 hours moving upstream. The time taken to cover the same distance in still water is

A particle of mass m is moving with constant velocity v parallel to x-axis in x-y plane as shown in figure. Calculate its angular momentum with respect to origin at anyinstant 't'.

If a displacement vector of AB is ^i+^j+2^k and point A having a position vector 2^i+5^j+6^k, then find the position vector of B ?

A force of 15 N displaces a box on a horizontal surface through a distance of 10 m. Calculate the angle which the force makes with the direction of motion of the body, if work done is 75 J.

A showman comes running and stands at the centre of the rotating platform.Considering the platform and the showman a system,which of the following is conserved? 1. Linear momentum 2. Angular momentum 3.kinetice energy 4. None of the above

Why is radium used for therapy of cancer instead it was the reason of Pierre curie's death due to exposure of radium for a long time?

When 2g of a gas A is introduced into an evacuated flask kept at 250 C, the pressure is found to be 1 atmosphere. If 3g of another gas is then added to the same flask, the total pressure becomes 1.5 atm. Assuming ideal behaviour, the ratio of their molecular weights MA : MB is

Can satellite revolving around the earth be taken as simple harmonic motion?(give clear explanation)

Three rods of the same mass are placed as shown in the figure. The co-ordinates of the centre of mass of the system is

We say that the universe is constantly expanding. The area of the universe was certain in the past. In which area is the universe expanding

A body is being moved along a straight line by a machine delivering a constant power. The distance covered by the body in time t is proportional to

A 10 kg weight is raused to a height of 2 m wth an acceleration of 1.5 m/sec square .compute the work done if g = 10 m/sec square

The energy of a photon is 3 × 10−12 ergs. What is its wavelength in nm ? (h = 6.62 × 10−27 erg.Sec; c = 3 × 1010cm.s−1)

The magnetic field due to a current carrying circular loop of radius 3 cm at a point on its axis at a distance of 4 cm from the centre is 54 μT. The magnetic field (in μT) at the centre of the loop will be

For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery Is this above statement true. ??

How is resonance frequency related to a radio or how is a quality factor affect the radio ?

Why the value of g is more at the poles than at the equator of the earth?

An ant moves from A to B and then comes back to point A and reaches C. Find the distance (d) and displacement (s) of the ant in this entire journey.

At what temperature the RMS velocity of SO2 be same as that of O2 at 303 K

Which of the following is called a fictitious force?

Referring to a - x graph, find the velocity when the displacement of the particle is 100 m. assume initial velocity as zero.

The equation y = 0.15 sin 5 x cos 300 t , describes a stationary wave. The wavelength of the stationary wave is [MP PMT 1995]

What dose a polaroid consist of? Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why

A particle moves in the x-y plane under the action of a force →F=−2k sin kt(^i+^j) at any time t its linear momentum is given by Px=2cos(kt)andPy=2cos(kt) The angle between →F and→P at time t is