50278 + Interview Questions in Physics Page 178 InterviewSolution

8851.	A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference of V esu. If e and m are charge and mass of an electron, respectively, then the value of hλ (where, λ is wavelength associated with electron) is given by:
Answer» A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference of $V esu$ . If $e$ and $m$ are charge and mass of an electron, respectively, then the value of $\frac{h}{λ}$ (where, $λ$ is wavelength associated with electron) is given by:

Discussion

8852.	A man is standing on a weighing machine placed in a lift, when stationary, his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of 2m/s2, then the weight recorded in the machine will be (g=10m/s2)
Answer» A man is standing on a weighing machine placed in a lift, when stationary, his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of $2 m / s^{2}$ , then the weight recorded in the machine will be $(g = 10 m / s^{2})$

Discussion

8853.	How many forces would be acting on M when its FBD is considered?
Answer» How many forces would be acting on $M$ when its $F B D$ is considered?

Discussion

8854.	A boy playing on the roof of a 10 m high building throws a ball with a speed of 10 m/s at an angle of 30∘ with the horizontal. The time taken by the ball to cross the point which is at the height of 10 m from the ground is
Answer» A boy playing on the roof of a $10 m$ high building throws a ball with a speed of $10 m / s$ at an angle of $30^{\circ}$ with the horizontal. The time taken by the ball to cross the point which is at the height of $10 m$ from the ground is

Discussion

8855.	20. 135 gram of water is electrolysed during an experiment. if the efficiency of current is 75% then select the correct statement. (1) 168 L of O2 will be evolved at anode at STP (2) 84 L of H2 will be evolved at cathode at STP (3) 15 F electricity will be consumed (4) 20 F electricity will be consumed
Answer» 20. 135 gram of water is electrolysed during an experiment. if the efficiency of current is 75% then select the correct statement. (1) 168 L of O2 will be evolved at anode at STP (2) 84 L of H2 will be evolved at cathode at STP (3) 15 F electricity will be consumed (4) 20 F electricity will be consumed

Discussion

8856.	A rocket is in gravity free space. A scientist wants the acceleration of the rocket to be 2 m/s2. Initial mass of the rocket is 1000 kg and the speed of ejection of burnt fuel w.r.t the rocket is 500 m/s. Find the rate of consumption of fuel (in kg/s), so that the rocket will have an acceleration of 2 m/s2.
Answer» A rocket is in gravity free space. A scientist wants the acceleration of the rocket to be $2 {m/s}^{2}$ . Initial mass of the rocket is $1000 kg$ and the speed of ejection of burnt fuel w.r.t the rocket is $500 m/s$ . Find the rate of consumption of fuel $(in kg/s)$ , so that the rocket will have an acceleration of $2 {m/s}^{2} .$

Discussion

8857.	Column IColumn IIa. Nature and order of interferencep. Bright fringe of order 80at the point P, OP = 10 mmb. Nature and order of q. Bright fringe of order 262interference at point Oc. If a transparent paper (refractive)r. Bright fringe of order 62indexμ=1.45) of thickness t=0.02 mmis pasted on S1,i.e. one of the slits, thenature and order of the interference at Pd. After inserting the transparent papers. Bright fringe of order 280in front of slit S1,the nature and orderof interference at O Two coherent point sources S1 and S2 vibrating in phase emit light of wavelength λ. The separation between the sources is 2λ. Consider a line passing through S2 and perpendicular to the line S1S2. Find the position of farthest and nearest minima.
Answer» $Column IColumn IIa. Nature and order of interferencep. Bright fringe of order 80at the point P, OP = 10 mmb. Nature and order of q. Bright fringe of order 262interference at point Oc. If a transparent paper (refractive)r. Bright fringe of order 62indexμ=1.45) of thickness t=0.02 mmis pasted on S1,i.e. one of the slits, thenature and order of the interference at Pd. After inserting the transparent papers. Bright fringe of order 280in front of slit S1,the nature and orderof interference at O$ Two coherent point sources $S_{1}$ and $S_{2}$ vibrating in phase emit light of wavelength $λ$ . The separation between the sources is $2 λ$ . Consider a line passing through $S_{2}$ and perpendicular to the line $S_{1} S_{2}$ . Find the position of farthest and nearest minima.

Discussion

8858.	The equation of a progressive wave is y=0.03sin2π[t0.01−x0.30], where x and y are in metres and t is in seconds. The velocity of propagation of the wave is (in m/s)
Answer» The equation of a progressive wave is $y = 0.03 sin 2 π [\frac{t}{0.01} - \frac{x}{0.30}]$ , where $x$ and $y$ are in metres and $t$ is in seconds. The velocity of propagation of the wave is (in $m/s$ )

Discussion

8859.	23. A boy on a 78.4-m-high cliff drops a stone. Onesecond later, he throws another stone downwardswith some speed. The two stones reach the groundsimultaneously. Find the speed with which thedsecond stone was thrown.ohue
Answer» 23. A boy on a 78.4-m-high cliff drops a stone. Onesecond later, he throws another stone downwardswith some speed. The two stones reach the groundsimultaneously. Find the speed with which thedsecond stone was thrown.ohue

Discussion

8860.	Equal masses of water and a liquid of density 2 are mixed together, then the mixture has a density of
Answer» Equal masses of water and a liquid of density 2 are mixed together, then the mixture has a density of

Discussion

8861.	A bullet of mass 'm' hits a target of mass M hanging by a string and gets embedded in it. If the block rises to a height h as a result of this collision, the velocity of the bullet before collision is
Answer» A bullet of mass 'm' hits a target of mass M hanging by a string and gets embedded in it. If the block rises to a height h as a result of this collision, the velocity of the bullet before collision is

Discussion

8862.	A particle starts from rest, accelerates at 2 m/s2 for 10 s and then goes with constant speed for 30 s and then decelerates at 4 m/s2 till it stops. What is the distance travelled by it?
Answer» A particle starts from rest, accelerates at $2 {m/s}^{2}$ for $10 s$ and then goes with constant speed for $30 s$ and then decelerates at $4 {m/s}^{2}$ till it stops. What is the distance travelled by it?

Discussion

8863.	28. what will be the volume chanGBe if 500j of the work is done by the system containing an ideal gas the surrounding exert a constant pressure of 5 atms ltr
Answer» 28. what will be the volume chanGBe if 500j of the work is done by the system containing an ideal gas the surrounding exert a constant pressure of 5 atms ltr

Discussion

8864.	42. A body is falling from rest at certain height the distance covered by body in first 3 sec is equal is equal to distance covered by body in last 3 sec before striking. How long body remains in air?
Answer» 42. A body is falling from rest at certain height the distance covered by body in first 3 sec is equal is equal to distance covered by body in last 3 sec before striking. How long body remains in air?

Discussion

8865.	Three objects, A: (a solid sphere), B: (a thin circular disc ) and C: (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed ω about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation
Answer» Three objects, $A :$ (a solid sphere), $B :$ (a thin circular disc ) and $C :$ (a circular ring), each have the same mass $M$ and radius $R$ . They all spin with the same angular speed $ω$ about their own symmetry axes. The amounts of work $(W)$ required to bring them to rest, would satisfy the relation

Discussion

8866.	39. Why their is need for reference standards and what are significant figures also explains briefly about scientific notation and their use in addition , subtraction multiplication or division
Answer» 39. Why their is need for reference standards and what are significant figures also explains briefly about scientific notation and their use in addition , subtraction multiplication or division

Discussion

8867.	The equation of the line passing through the points (4,−2) and (−3,3) is
Answer» The equation of the line passing through the points $(4, - 2)$ and $(- 3, 3)$ is

Discussion

8868.	10 gm of ice cubes at 0∘C are released in a tumbler (water equivalent 55 gm) at 40∘C. Assuming that negligible heat is taken from the surroundings, the temperature of water in the tumbler becomes nearly (L=80 cal/g)
Answer» $10 gm$ of ice cubes at $0^{\circ} C$ are released in a tumbler (water equivalent $55 gm$ ) at $40^{\circ} C$ . Assuming that negligible heat is taken from the surroundings, the temperature of water in the tumbler becomes nearly ( $L = 80$ $cal/g$ )

Discussion

8869.	A plane flies 10 km east from city A to city B in 2 hrs and then 20 km south from city B to city C in 1 hr. For the total trip, what are the magnitude and direction of its average acceleration?
Answer» A plane flies 10 km east from city A to city B in 2 hrs and then 20 km south from city B to city C in 1 hr. For the total trip, what are the magnitude and direction of its average acceleration?

Discussion

8870.	A signal xt is given as, and another signal x2is given as, Both the signal are sampled at 1000 samples/sec,then the ratioof time period of x2(t) to x1(t) after sampling is..... x1(t)=4sin(10πt) x2=16cos(π2t+60∘)20
Answer» $A s i g n a l x_{t} i s g i v e n a s, a n d a n o t h e r s i g n a l x_{2} i s g i v e n a s, B o t h t h e s i g n a l a r e s a m p l e d a t 1000 s a m p l e s / s e c, t h e n t h e r a t i o o f t i m e p e r i o d o f x_{2} (t) t o x_{1} (t) a f t e r s a m p l i n g i s . . . . . x_{1} (t) = 4 s i n (10 π t) x_{2} = 16 c o s (\frac{π}{2} t + 60^{\circ})$ 20

Discussion

8871.	11. A q charge placed at the corner of a cube. Then total flux link through the opposite surface
Answer» 11. A q charge placed at the corner of a cube. Then total flux link through the opposite surface

Discussion

8872.	A thick conductor having inner radius a and outer radius b has a small passage as shown in the figure.A charge +Q is placed at the centre. The work done by external agent in taking the charge from centre to infinity is
Answer» A thick conductor having inner radius $a$ and outer radius $b$ has a small passage as shown in the figure. A charge $+ Q$ is placed at the centre. The work done by external agent in taking the charge from centre to infinity is

Discussion

8873.	Two spheres of mass m and M of the same radius R, are separated by a distance √8R. The force of attraction between them is:
Answer» Two spheres of mass $m$ and $M$ of the same radius $R$ , are separated by a distance $\sqrt{8} R$ . The force of attraction between them is:

Discussion

8874.	Forany arbitrary motion in space, which of the following relations aretrue:(a) (b) (c) (d) (e) (The‘average’ stands for average of the quantity over thetime interval t1to t2)
Answer» For any arbitrary motion in space, which of the following relations are true: (a) (b) (c) (d) (e) (The ‘average’ stands for average of the quantity over the time interval t₁ to t₂)

8874.

Forany arbitrary motion in space, which of the following relations aretrue:(a) (b) (c) (d) (e) (The‘average’ stands for average of the quantity over thetime interval t1to t2)

Answer»

For
any arbitrary motion in space, which of the following relations are
true:

(a)

(b)

(c)

(d)

(e)

(The
‘average’ stands for average of the quantity over the
time interval t₁
to t₂)

Discussion

8875.	Two parallel plate capacitors A and B having capacitance 2 μF and 3 μF are charged separately up to 20 V and 10 V respectively. Now, the positive plate of A is connected to the positive plate of B and negative plate of A is connected with negative plate of B. Find how much charge flows in the circuit?
Answer» Two parallel plate capacitors $A$ and $B$ having capacitance $2 μ F$ and $3 μ F$ are charged separately up to $20 V$ and $10 V$ respectively. Now, the positive plate of $A$ is connected to the positive plate of $B$ and negative plate of $A$ is connected with negative plate of $B$ . Find how much charge flows in the circuit?

Discussion

8876.	A proton and a Li+ ion are moving towards a gold foil. If their distance of the closest approach are equal, find vLI+vα.
Answer» A proton and a ${Li}^{+}$ ion are moving towards a gold foil. If their distance of the closest approach are equal, find $\frac{v_{L I^{+}}}{v_{α}}$ .

Discussion

8877.	Charge between parallel plates : Surface charge density is defined as the charge per unit surface area of surface charge distribution. i.e., σ=qSTwo large thin metal plates are parallel and close to each other, on their inner faces, the plates have surface charge densities of opposite sign having magnitude of 1.70×10−22 Cm−2 as shown in figure.[Use ε0=8.85×10−12 Fm−1](i) The electric field E in the region in between the plates A and B is
Answer» Charge between parallel plates : Surface charge density is defined as the charge per unit surface area of surface charge distribution. i.e., $σ = \frac{q}{S}$ Two large thin metal plates are parallel and close to each other, on their inner faces, the plates have surface charge densities of opposite sign having magnitude of $1.70 \times 10^{- 22} {Cm}^{- 2}$ as shown in figure. [Use $ε_{0} = 8.85 \times 10^{- 12} {Fm}^{- 1}$ ] $(i)$ The electric field $E$ in the region in between the plates $A$ and $B$ is

Discussion

8878.	a point charge q is placed over a horizontal square of side L at normal dis†an ce of L/4 from its centre. Electric flux through square is
Answer» a point charge q is placed over a horizontal square of side L at normal dis†an ce of L/4 from its centre. Electric flux through square is

Discussion

8879.	What is the dimensional formula of magnetic vector potential?
Answer» What is the dimensional formula of magnetic vector potential?

Discussion

8880.	A particle of mass 0.01 kg travels with a velocity given by 4^i+16^k ms−1. After sometime, its velocity becomes 8^i+20^j ms−1. The work done on particle during this interval of time is
Answer» A particle of mass $0.01 kg$ travels with a velocity given by $4^i + 16^k {ms}^{- 1}$ . After sometime, its velocity becomes $8^i + 20^j {ms}^{- 1}$ . The work done on particle during this interval of time is

Discussion

8881.	The equation of projectile is y=16x−5x24. The horizontal range is-
Answer» The equation of projectile is $y = 16 x - \frac{5 x^{2}}{4}$ . The horizontal range is-

Discussion

8882.	if y = 1/a-z , what is dy/dz
Answer» if y = 1/a-z , what is dy/dz

Discussion

8883.	A motorcycle starts from rest and accelerates along a straight line at 2.2 m/s2. The speed of sound is 330 m/s. A siren at the starting point remains stationary. When the driver hears the frequency of the siren at 90% of the frequency heard when the motorcycle is stationary, the distance travelled by the motorcyclist from his initial position is
Answer» A motorcycle starts from rest and accelerates along a straight line at $2.2 {m/s}^{2} .$ The speed of sound is $330 m/s$ . A siren at the starting point remains stationary. When the driver hears the frequency of the siren at 90% of the frequency heard when the motorcycle is stationary, the distance travelled by the motorcyclist from his initial position is

Discussion

8884.	The total kinetic energy in joules of the molecuein 8 g of methane at 27 C is(1) 3741 30 J(2) 935.3J3) 1870.65 J(4) 700
Answer» The total kinetic energy in joules of the molecuein 8 g of methane at 27 C is(1) 3741 30 J(2) 935.3J3) 1870.65 J(4) 700

Discussion

8885.	In a region, the potential is represented by V(x,y,z)=6x−8xy−8y+6yz, where V is in volts and x,y,z are in meters. The electric force experienced by a charge of 2coulomb situated at point (1,1,1) is
Answer» In a region, the potential is represented by $V (x, y, z) = 6 x - 8 x y - 8 y + 6 y z$ , where $V$ is in volts and $x, y, z$ are in meters. The electric force experienced by a charge of $2$ coulomb situated at point $(1, 1, 1)$ is

Discussion

8886.	A mixture of ideal gases has 2 moles of He,4 moles of oxygen and 1 mole of ozone at absolutetemperature T. The internal energy of mixture is(1) 13 RT(3) 16 RT(2) 11 RT(4) 14 RT
Answer» A mixture of ideal gases has 2 moles of He,4 moles of oxygen and 1 mole of ozone at absolutetemperature T. The internal energy of mixture is(1) 13 RT(3) 16 RT(2) 11 RT(4) 14 RT

Discussion

8887.	If L represents angular momentum and P represents linear momentum then the variation of log L and log P is correctly shown by
Answer» If $L$ represents angular momentum and $P$ represents linear momentum then the variation of $log L$ and $log P$ is correctly shown by

Discussion

8888.	A capacitor is charged until it stores an energy of1 J. A second uncharged capacitor is connectedto it, so that charge distributes equally. The finalenergy stored in the second capacitor is
Answer» A capacitor is charged until it stores an energy of1 J. A second uncharged capacitor is connectedto it, so that charge distributes equally. The finalenergy stored in the second capacitor is

Discussion

8889.	In a series LCR AC circuit RMS voltage of L,Cand R are V1,V2 and V3 respectively then A. equal toV1+V2+V3 B. Equal to V1-V2+V3 C. More than V1+V2+V3 D. None of these
Answer» In a series LCR AC circuit RMS voltage of L,Cand R are V1,V₂ and V3 respectively then A. equal toV1+V2+V3 B. Equal to V1-V2+V3 C. More than V1+V2+V3 D. None of these

Discussion

8890.	Find the electric field at the symmetric centre.
Answer» Find the electric field at the symmetric centre.

Discussion

8891.	Two particles of mass 'm' and charge 'q' each are suspended by means of two silk threads of length 'l' each from the same point. If they are taken into an artificial satellite, the angle between the threads in equilibrium is
Answer» Two particles of mass 'm' and charge 'q' each are suspended by means of two silk threads of length 'l' each from the same point. If they are taken into an artificial satellite, the angle between the threads in equilibrium is

Discussion

8892.	If the compressibility of water is σ per unit atmospheric pressure, then the decrease in volume V due to P atmospheric pressure will be
Answer» If the compressibility of water is σ per unit atmospheric pressure, then the decrease in volume V due to P atmospheric pressure will be

Discussion

8893.	If ε0 and μ0 are respectively, the electric permittivity and magnetic permeability of free space, ε and μ the corresponding quantities in a medium, the refractive index of the medium is
Answer» If $ε_{0}$ and $μ_{0}$ are respectively, the electric permittivity and magnetic permeability of free space, $ε$ and $μ$ the corresponding quantities in a medium, the refractive index of the medium is

Discussion

8894.	18.In case of person of height h ,why it is prescribed to take plane mirror of height h/2
Answer» 18.In case of person of height h ,why it is prescribed to take plane mirror of height h/2

Discussion

8895.	Find the acceleration due to gravity of the moon at a point 1000 km above the moon's surface. The mass of the moon is 7.4×1022 kg and its radius is 1740 km.
Answer» Find the acceleration due to gravity of the moon at a point 1000 km above the moon's surface. The mass of the moon is $7.4 \times 10^{22}$ kg and its radius is 1740 km.

Discussion

8896.	Figure9.37 shows an equiconvex lens (of refractive index 1.50) in contactwith a liquid layer on top of a plane mirror. A small needle with itstip on the principal axis is moved along the axis until its invertedimage is found at the position of the needle. The distance of theneedle from the lens is measured to be 45.0 cm. The liquid is removedand the experiment is repeated. The new distance is measured to be30.0 cm. What is the refractive index of the liquid?
Answer» Figure 9.37 shows an equiconvex lens (of refractive index 1.50) in contact with a liquid layer on top of a plane mirror. A small needle with its tip on the principal axis is moved along the axis until its inverted image is found at the position of the needle. The distance of the needle from the lens is measured to be 45.0 cm. The liquid is removed and the experiment is repeated. The new distance is measured to be 30.0 cm. What is the refractive index of the liquid?

8896.

Figure9.37 shows an equiconvex lens (of refractive index 1.50) in contactwith a liquid layer on top of a plane mirror. A small needle with itstip on the principal axis is moved along the axis until its invertedimage is found at the position of the needle. The distance of theneedle from the lens is measured to be 45.0 cm. The liquid is removedand the experiment is repeated. The new distance is measured to be30.0 cm. What is the refractive index of the liquid?

Answer»

Figure
9.37 shows an equiconvex lens (of refractive index 1.50) in contact
with a liquid layer on top of a plane mirror. A small needle with its
tip on the principal axis is moved along the axis until its inverted
image is found at the position of the needle. The distance of the
needle from the lens is measured to be 45.0 cm. The liquid is removed
and the experiment is repeated. The new distance is measured to be
30.0 cm. What is the refractive index of the liquid?

Discussion

8897.	A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m, 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work is done only when the weight is lifted up? Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate. Take g=9.8 ms−2.
Answer» A person trying to lose weight by burning fat lifts a mass of $10 k g$ upto a height of $1 m$ , $1000$ times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work is done only when the weight is lifted up? Fat supplies $3.8 \times 10^{7} J$ of energy per $k g$ which is converted to mechanical energy with a $20 %$ efficiency rate. Take $g = 9.8 m s^{- 2}$ .

Discussion

8898.	Two balls of masses, 3 kg and 5 kg are moving as shown in the figure. After the collision, both the balls moves together. Their common velocity after collision is -
Answer» Two balls of masses, $3 kg$ and $5 kg$ are moving as shown in the figure. After the collision, both the balls moves together. Their common velocity after collision is -

Discussion

8899.	The distance of the lens from the film can be changed by
Answer» The distance of the lens from the film can be changed by

Discussion

8900.	A concave mirror of focal length f produces an image n times the size of an object.If the image is real then the dis†an ce of the object from the mirror is?
Answer» A concave mirror of focal length f produces an image n times the size of an object.If the image is real then the dis†an ce of the object from the mirror is?

Discussion

Explore topic-wise InterviewSolutions in .

A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference of V esu. If e and m are charge and mass of an electron, respectively, then the value of hλ (where, λ is wavelength associated with electron) is given by:

A man is standing on a weighing machine placed in a lift, when stationary, his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of 2m/s2, then the weight recorded in the machine will be (g=10m/s2)

How many forces would be acting on M when its FBD is considered?

A boy playing on the roof of a 10 m high building throws a ball with a speed of 10 m/s at an angle of 30∘ with the horizontal. The time taken by the ball to cross the point which is at the height of 10 m from the ground is

The equation of a progressive wave is y=0.03sin2π[t0.01−x0.30], where x and y are in metres and t is in seconds. The velocity of propagation of the wave is (in m/s)

23. A boy on a 78.4-m-high cliff drops a stone. Onesecond later, he throws another stone downwardswith some speed. The two stones reach the groundsimultaneously. Find the speed with which thedsecond stone was thrown.ohue

Equal masses of water and a liquid of density 2 are mixed together, then the mixture has a density of

A bullet of mass 'm' hits a target of mass M hanging by a string and gets embedded in it. If the block rises to a height h as a result of this collision, the velocity of the bullet before collision is

A particle starts from rest, accelerates at 2 m/s2 for 10 s and then goes with constant speed for 30 s and then decelerates at 4 m/s2 till it stops. What is the distance travelled by it?

28. what will be the volume chanGBe if 500j of the work is done by the system containing an ideal gas the surrounding exert a constant pressure of 5 atms ltr

42. A body is falling from rest at certain height the distance covered by body in first 3 sec is equal is equal to distance covered by body in last 3 sec before striking. How long body remains in air?

Three objects, A: (a solid sphere), B: (a thin circular disc ) and C: (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed ω about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation

39. Why their is need for reference standards and what are significant figures also explains briefly about scientific notation and their use in addition , subtraction multiplication or division

The equation of the line passing through the points (4,−2) and (−3,3) is

10 gm of ice cubes at 0∘C are released in a tumbler (water equivalent 55 gm) at 40∘C. Assuming that negligible heat is taken from the surroundings, the temperature of water in the tumbler becomes nearly (L=80 cal/g)

A plane flies 10 km east from city A to city B in 2 hrs and then 20 km south from city B to city C in 1 hr. For the total trip, what are the magnitude and direction of its average acceleration?

A signal xt is given as, and another signal x2is given as, Both the signal are sampled at 1000 samples/sec,then the ratioof time period of x2(t) to x1(t) after sampling is..... x1(t)=4sin(10πt) x2=16cos(π2t+60∘)20

11. A q charge placed at the corner of a cube. Then total flux link through the opposite surface

A thick conductor having inner radius a and outer radius b has a small passage as shown in the figure.A charge +Q is placed at the centre. The work done by external agent in taking the charge from centre to infinity is

Two spheres of mass m and M of the same radius R, are separated by a distance √8R. The force of attraction between them is:

Forany arbitrary motion in space, which of the following relations aretrue:(a) (b) (c) (d) (e) (The‘average’ stands for average of the quantity over thetime interval t1to t2)

A proton and a Li+ ion are moving towards a gold foil. If their distance of the closest approach are equal, find vLI+vα.

a point charge q is placed over a horizontal square of side L at normal dis†an ce of L/4 from its centre. Electric flux through square is

What is the dimensional formula of magnetic vector potential?

A particle of mass 0.01 kg travels with a velocity given by 4^i+16^k ms−1. After sometime, its velocity becomes 8^i+20^j ms−1. The work done on particle during this interval of time is

The equation of projectile is y=16x−5x24. The horizontal range is-

if y = 1/a-z , what is dy/dz

The total kinetic energy in joules of the molecuein 8 g of methane at 27 C is(1) 3741 30 J(2) 935.3J3) 1870.65 J(4) 700

In a region, the potential is represented by V(x,y,z)=6x−8xy−8y+6yz, where V is in volts and x,y,z are in meters. The electric force experienced by a charge of 2coulomb situated at point (1,1,1) is

A mixture of ideal gases has 2 moles of He,4 moles of oxygen and 1 mole of ozone at absolutetemperature T. The internal energy of mixture is(1) 13 RT(3) 16 RT(2) 11 RT(4) 14 RT

If L represents angular momentum and P represents linear momentum then the variation of log L and log P is correctly shown by

A capacitor is charged until it stores an energy of1 J. A second uncharged capacitor is connectedto it, so that charge distributes equally. The finalenergy stored in the second capacitor is

In a series LCR AC circuit RMS voltage of L,Cand R are V1,V2 and V3 respectively then A. equal toV1+V2+V3 B. Equal to V1-V2+V3 C. More than V1+V2+V3 D. None of these

Find the electric field at the symmetric centre.

Two particles of mass 'm' and charge 'q' each are suspended by means of two silk threads of length 'l' each from the same point. If they are taken into an artificial satellite, the angle between the threads in equilibrium is

If the compressibility of water is σ per unit atmospheric pressure, then the decrease in volume V due to P atmospheric pressure will be

If ε0 and μ0 are respectively, the electric permittivity and magnetic permeability of free space, ε and μ the corresponding quantities in a medium, the refractive index of the medium is

18.In case of person of height h ,why it is prescribed to take plane mirror of height h/2

Find the acceleration due to gravity of the moon at a point 1000 km above the moon's surface. The mass of the moon is 7.4×1022 kg and its radius is 1740 km.

Two balls of masses, 3 kg and 5 kg are moving as shown in the figure. After the collision, both the balls moves together. Their common velocity after collision is -

The distance of the lens from the film can be changed by

A concave mirror of focal length f produces an image n times the size of an object.If the image is real then the dis†an ce of the object from the mirror is?