50278 + Interview Questions in Physics

1.	What is trajectory?
Answer» What is trajectory?

Discussion

2.	Akash placed a candle in front of a convex lens and obtained an image as shown below. Now he covered the upper half of the lens with a black paper. What can you say about the image formed?
Answer» Akash placed a candle in front of a convex lens and obtained an image as shown below. Now he covered the upper half of the lens with a black paper. What can you say about the image formed?

2.

Akash placed a candle in front of a convex lens and obtained an image as shown below. Now he covered the upper half of the lens with a black paper. What can you say about the image formed?

Answer»

Akash placed a candle in front of a convex lens and obtained an image as shown below.

Now he covered the upper half of the lens with a black paper. What can you say about the image formed?

Discussion

3.	A current-carrying circular coil of 100 turns and radius 5.0 cm produces a magnetic field of 6.0×10−5 T at its centre. Find the value of the current.
Answer» A current-carrying circular coil of 100 turns and radius 5.0 cm produces a magnetic field of $6.0 \times 10^{- 5 T}$ at its centre. Find the value of the current.

Discussion

4.	For a satellite escape velocity is 11 km / s. If the satellite is launched at an angle of 60∘ with the vertical, then escape velocity will be
Answer» For a satellite escape velocity is 11 km / s. If the satellite is launched at an angle of $60^{\circ}$ with the vertical, then escape velocity will be

Discussion

5.	Liquid is kept in a container having square cross section. It is now accelerated from left to right with an acceleration of 5 m/s2. Due to this the free surface makes some inclination with horizontal. If the length of the square cross section is 10 m, find the difference in heights of liquid at the left and the right wall. (Take g=10 m/s2)
Answer» Liquid is kept in a container having square cross section. It is now accelerated from left to right with an acceleration of $5 {m/s}^{2}$ . Due to this the free surface makes some inclination with horizontal. If the length of the square cross section is $10 m$ , find the difference in heights of liquid at the left and the right wall. (Take $g = 10 {m/s}^{2}$ )

Discussion

6.	What are the common barriers to effective communication? Suggest measures to overcome them.
Answer» What are the common barriers to effective communication? Suggest measures to overcome them.

Discussion

7.	Which of the following is paramagnetic
Answer» Which of the following is paramagnetic

Discussion

8.	A combination of secondary cells has an equivalent EMF of 2 V. Due to long use they have a large equivalent resistance of 400 Ω. What maximum current can be drawn?
Answer» A combination of secondary cells has an equivalent EMF of 2 V. Due to long use they have a large equivalent resistance of 400 $Ω$ . What maximum current can be drawn?

Discussion

9.	With increase in temperature, the resistivity of a semiconductor?
Answer» With increase in temperature, the resistivity of a semiconductor?

Discussion

10.	A sound source, fixed at the origin, is continuously emitting sound at a frequency of 660 Hz. The sound travels in air at a speed of 330ms−1. A listener is moving along the line x = 336 m at a constant speed of 26ms−1. Find the frequency of the sound as observed by the listener when he is (a) at y = -140 m, (b) at y = 0 and (c) at y = 140 m.
Answer» A sound source, fixed at the origin, is continuously emitting sound at a frequency of 660 Hz. The sound travels in air at a speed of $330 m s^{- 1}$ . A listener is moving along the line x = 336 m at a constant speed of $26 m s^{- 1}$ . Find the frequency of the sound as observed by the listener when he is (a) at y = -140 m, (b) at y = 0 and (c) at y = 140 m.

Discussion

11.	The horizontal range of an oblique projectile is equal to the distance through which a projectile has to fall freely from rest to acquire a velocity equal to the velocity of projection in magnitude. The angle of projection is
Answer» The horizontal range of an oblique projectile is equal to the distance through which a projectile has to fall freely from rest to acquire a velocity equal to the velocity of projection in magnitude. The angle of projection is

Discussion

12.	If CP and CV denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then
Answer» If $C_{P}$ and $C_{V}$ denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then

Discussion

13.	When the temperature of a black body increase by 0.1%, the wavelength corresponding to maximum emission changes by 0.13 μm. The initial wavelength corresponding to maximum emission is
Answer» When the temperature of a black body increase by $0.1 %$ , the wavelength corresponding to maximum emission changes by 0.13 $μ$ m. The initial wavelength corresponding to maximum emission is

Discussion

14.	Both the strings, shown in figure, are made of same material and have same cross section. The pulleys are light. The wave speed of a transverse wave in the string AB is v1 and in CD it is v2. The v1v2 is
Answer» Both the strings, shown in figure, are made of same material and have same cross section. The pulleys are light. The wave speed of a transverse wave in the string $A B$ is $v_{1}$ and in $C D$ it is $v_{2}$ . The $\frac{v_{1}}{v_{2}}$ is

Discussion

15.	Voltage of modulating wave of 5 V with 10 MHz frequency, was superimposed on carrier wave of frequency 20 MHz & 20 V, then the modulation index is given by 1/x. Find x.
Answer» Voltage of modulating wave of $5 V$ with $10 MHz$ frequency, was superimposed on carrier wave of frequency $20 MHz$ & $20 V$ , then the modulation index is given by $1 / x$ . Find $x$ .

Discussion

16.	The displacement x of a particle varies with time t as x=A sin2 ωt+B cos2 ωt+C sin ωt cos ωt For what values of A, B and C is the motion simple harmonic?
Answer» The displacement x of a particle varies with time t as $x = A s i n^{2} ω t + B c o s^{2} ω t + C s i n ω t c o s ω t$ For what values of A, B and C is the motion simple harmonic?

Discussion

17.	A man of mass M=50 kg stands at one end of the boat which is floating on still water. The man walks to the other end of the boat. Length of the boat is L=10 m and mass M′=100 kg. Then find the distance moved by the boat relative to the ground
Answer» A man of mass $M = 50 kg$ stands at one end of the boat which is floating on still water. The man walks to the other end of the boat. Length of the boat is $L = 10 m$ and mass $M^{'} = 100 kg$ . Then find the distance moved by the boat relative to the ground

Discussion

18.	A piston of mass m =0.005 kg and area of cross section S=0.1m2 is placed near one end of open organ pipe of length L=πm and area of cross section S. At the other end a tuning fork of frequency f produces a traveling sound wave of displacement amplitude A, which excites the pipe in to second overtone. The coefficient of friction between piston and ground is μ=0.1. Find the value of A (in micrometer) at which the piston is about to shift towards left from the pipe. Given bulk modulus of medium in the pipe is 104N/m2.
Answer» A piston of mass m =0.005 kg and area of cross section $S = 0.1 m^{2}$ is placed near one end of open organ pipe of length $L = π m$ and area of cross section S. At the other end a tuning fork of frequency f produces a traveling sound wave of displacement amplitude A, which excites the pipe in to second overtone. The coefficient of friction between piston and ground is $μ = 0.1$ . Find the value of A (in micrometer) at which the piston is about to shift towards left from the pipe. Given bulk modulus of medium in the pipe is $10^{4} N / m^{2}$ .

Discussion

19.	Two identical simple pendulums A and B have the same point of suspension, having length ℓ each. They are displaced by an angle (α and β are very small and β>α) and released from rest. Find the time after which B reaches its initial position for the first time. Assume collision to be elastic and both pendulums move in the same plane.
Answer» Two identical simple pendulums A and B have the same point of suspension, having length $ℓ$ each. They are displaced by an angle ( $α$ and $β$ are very small and $β > α$ ) and released from rest. Find the time after which B reaches its initial position for the first time. Assume collision to be elastic and both pendulums move in the same plane.

Discussion

20.	An electron is accelerated through a potential difference of 1000 volt. The velocity acquired by the electron is
Answer» An electron is accelerated through a potential difference of 1000 volt. The velocity acquired by the electron is

Discussion

21.	Two large parallel metallic plates are given charge Q and 2Q as shown in figure. Which graph show variation of electric field as a function of x. [Take ideal condition]
Answer» Two large parallel metallic plates are given charge Q and 2Q as shown in figure. Which graph show variation of electric field as a function of x. [Take ideal condition]

Discussion

22.	A stretched rope having linear mass density 5×10−2kgm−1 is under a tension of 80N. Power (in Watts) =648nπ2×10−2 has to be supplied to the rope to generate harmonic waves at a frequency of 60Hz and an amplitude of 6 cm. The value of n is___
Answer» A stretched rope having linear mass density $5 \times 10^{- 2} k g m^{- 1}$ is under a tension of 80N. Power (in Watts) $= 648 n π^{2} \times 10^{- 2}$ has to be supplied to the rope to generate harmonic waves at a frequency of 60Hz and an amplitude of 6 cm. The value of n is___

Discussion

23.	A hydrogen atom in its ground state is irradiated by light of wavelength 970 ˚A. Taking hce=1.237×10−6 eV and the ground state energy of hydrogen atom as −13.6 eV, the number of lines present in the emission spectrum is
Answer» A hydrogen atom in its ground state is irradiated by light of wavelength 970 $˚ A$ . Taking $\frac{h c}{e} = 1.237 \times 10^{- 6} e V$ and the ground state energy of hydrogen atom as $- 13.6 e V$ , the number of lines present in the emission spectrum is

Discussion

24.	A narrow monochromatic beam of light of intensity I is incident on a glass plate as shown in figure. Another identical glass plate is kept parallel to it. Each glass plate reflects 25% of the light incident on it and transmits the remaining. Then the ratio of the maximum to minimum intensities in the interference pattern formed by the two beams obtained after one reflection at each plate is.
Answer» A narrow monochromatic beam of light of intensity I is incident on a glass plate as shown in figure. Another identical glass plate is kept parallel to it. Each glass plate reflects 25% of the light incident on it and transmits the remaining. Then the ratio of the maximum to minimum intensities in the interference pattern formed by the two beams obtained after one reflection at each plate is.

24.

A narrow monochromatic beam of light of intensity I is incident on a glass plate as shown in figure. Another identical glass plate is kept parallel to it. Each glass plate reflects 25% of the light incident on it and transmits the remaining. Then the ratio of the maximum to minimum intensities in the interference pattern formed by the two beams obtained after one reflection at each plate is.

Answer»

A narrow monochromatic beam of light of intensity I is incident on a glass plate as shown in figure. Another identical glass plate is kept parallel to it. Each glass plate reflects 25% of the light incident on it and transmits the remaining. Then the ratio of the maximum to minimum intensities in the interference pattern formed by the two beams obtained after one reflection at each plate is.

Discussion

25.	A coil of resistance 20 Ω and inductance 5 H has been connected to a 100 V battery and the switch is closed at t=0. After how much time will the current acquire half of its steady state value. (ln2=0.693)
Answer» A coil of resistance $20 Ω$ and inductance $5 H$ has been connected to a $100 V$ battery and the switch is closed at $t = 0$ . After how much time will the current acquire half of its steady state value. ( $ln 2 = 0.693)$

Discussion

26.	Two parallel, conducting rails 1 and 2 are kept perpendicular to a uniform magnetic field (B). The rails are at seperation l and are joined at their ends by a resistance R. A conducting bar AB is placed on the rails making 60∘ with them. The bar is pulled with a velocity v parallel to the rails. Find the current in the resistance R.
Answer» Two parallel, conducting rails $1$ and $2$ are kept perpendicular to a uniform magnetic field $(B)$ . The rails are at seperation $l$ and are joined at their ends by a resistance $R$ . A conducting bar $A B$ is placed on the rails making $60^{\circ}$ with them. The bar is pulled with a velocity $v$ parallel to the rails. Find the current in the resistance $R$ .

Discussion

27.	Unit vector perpendicular to both→A and →B is
Answer» Unit vector perpendicular to both $\to A$ and $\to B$ is

Discussion

28.	How to derive the kinematic equations?
Answer» How to derive the kinematic equations?

Discussion

29.	A string is stretched between fixed points separated by 40 cm. It is observed to have consecutive resonant frequencies of 340 Hz and 510 Hz. Then, find the speed of wave on the string.
Answer» A string is stretched between fixed points separated by $40 c m$ . It is observed to have consecutive resonant frequencies of $340 H z$ and $510 H z$ . Then, find the speed of wave on the string.

Discussion

30.	Water flows through a horizontal pipe with a cross-sectional area of 2 m2 at a speed of 5 m/s with a pressure of 3×105 Pa at a point A. At point B, the cross-sectional area is 1 m2. Calculate the pressure at point B.
Answer» Water flows through a horizontal pipe with a cross-sectional area of $2 m^{2}$ at a speed of $5 m/s$ with a pressure of $3 \times 10^{5} Pa$ at a point $A$ . At point $B$ , the cross-sectional area is $1 m^{2}$ . Calculate the pressure at point $B$ .

Discussion

31.	If →a&→b are unit vectors, then angle between →a and →b for √3→a−→b to be unit vector is
Answer» If $\to a & \to b$ are unit vectors, then angle between $\to a$ and $\to b$ for $\sqrt{3} \to a - \to b$ to be unit vector is

Discussion

32.	Why shockers used in scooters and cars?
Answer» Why shockers used in scooters and cars?

Discussion

33.	The ratio of time taken by a body to slide down a smooth surface to rough identical inclined surface of angle θ is ‘n′. Find the coefficient of friction.
Answer» The ratio of time taken by a body to slide down a smooth surface to rough identical inclined surface of angle $θ$ is $‘ n^{'}$ . Find the coefficient of friction.

Discussion

34.	Evaluate the integrals using substitution. ∫10xx2+1dx.
Answer» Evaluate the integrals using substitution. $\int_{0}^{1} \frac{x}{x^{2} + 1} d x .$

Discussion

35.	A vessel contains 14 g of hydrogen and 96 g of oxygen at STP. Chemical reaction is induced by passing electric spark in the vessel till one of the gases is consumed. The temperature is brought back to its starting value 273 K. Find the pressure in the vessel.
Answer» A vessel contains 14 g of hydrogen and 96 g of oxygen at STP. Chemical reaction is induced by passing electric spark in the vessel till one of the gases is consumed. The temperature is brought back to its starting value 273 K. Find the pressure in the vessel.

Discussion

36.	Why we multiply 10-9 with wavelength,?
Answer» Why we multiply 10^-9with wavelength,?

Discussion

37.	The heat generated in a circuit is dependent upon the resistance, current and time for which the current is flown. if the error in measuring the above are 1% , 2% and 1% respectively than what will be the maximum error in measuring the heat
Answer» The heat generated in a circuit is dependent upon the resistance, current and time for which the current is flown. if the error in measuring the above are 1% , 2% and 1% respectively than what will be the maximum error in measuring the heat

Discussion

38.	A string can sustain a maximum force of 200 N without breaking. A block of mass of 1 kg is tied to one end of the string of 2 m long and the mass is rotated in a horizontal circular path. The maximum linear speed of mass is (in m/s).
Answer» A string can sustain a maximum force of $200 N$ without breaking. A block of mass of $1 kg$ is tied to one end of the string of $2 m$ long and the mass is rotated in a horizontal circular path. The maximum linear speed of mass is (in $m/s$ ).

Discussion

39.	An amount of charge Q is distributed between two particles. What should be the charges of the two particles so that the force of interaction between them is maximum?
Answer» An amount of charge Q is distributed between two particles. What should be the charges of the two particles so that the force of interaction between them is maximum?

Discussion

40.	The vapour density of a mixture containing NO2 and N2O4 is 38.3 at 27'C. Calculate moles of NO2 in 100 g of mixture.
Answer» The vapour density of a mixture containing NO2 and N2O4 is 38.3 at 27'C. Calculate moles of NO2 in 100 g of mixture.

Discussion

41.	two electrons held at distance r are released from rest . maximum kinetic energy obtained by electron is _. Options are A. Zero B.ke^2/r C.ke^2/2r D.ke^2/r^2
Answer» two electrons held at distance r are released from rest . maximum kinetic energy obtained by electron is _. Options are A. Zero B.ke^2/r C.ke^2/2r D.ke^2/r^2

41.

two electrons held at distance r are released from rest . maximum kinetic energy obtained by electron is _. Options are A. Zero B.ke^2/r C.ke^2/2r D.ke^2/r^2

Answer»

two electrons held at distance r are released from rest . maximum kinetic energy obtained by electron is _.

Options are

A. Zero

B.ke^2/r

C.ke^2/2r

D.ke^2/r^2

Discussion

42.	Two balls of masses 2 kg and 5 kg moving on a frictionless surface, collide head-on with speeds 2 m/s and 3 m/s as shown in figure. If the coefficient of restitution is 0.25, then the kinetic energy lost by the balls is
Answer» Two balls of masses $2 kg$ and $5 kg$ moving on a frictionless surface, collide head-on with speeds $2 m/s$ and $3 m/s$ as shown in figure. If the coefficient of restitution is $0.25$ , then the kinetic energy lost by the balls is

Discussion

43.	A rectangular lamina of mass 6 kg, breadth 4 m and length 6 m is taken as shown in figure. If Ix and Iy are the moments of inertia of the rectangular lamina about x− axis and y− axis respectively, then the value Iy+Ix is
Answer» A rectangular lamina of mass $6 kg$ , breadth $4 m$ and length $6 m$ is taken as shown in figure. If $I_{x}$ and $I_{y}$ are the moments of inertia of the rectangular lamina about $x -$ axis and $y -$ axis respectively, then the value $I_{y} + I_{x}$ is

Discussion

44.	Along an infinitely long conductor carrying a current of 8 A we keep another conductor of length 5 m carrying a current of 3 A. Both the conductors are 10 cm apart. Find the force on small conductor.
Answer» Along an infinitely long conductor carrying a current of 8 A we keep another conductor of length 5 m carrying a current of 3 A. Both the conductors are 10 cm apart. Find the force on small conductor.

Discussion

45.	four particles each of mass m are located at the vertices of a square of side L.the gravitational potential due to this at the center of the square is?? i wonder that why isnt the gravitational potential not cancelling acc to princip of superposition and also what does the negative sign in the answer imply?? pls reply fast
Answer» four particles each of mass m are located at the vertices of a square of side L.the gravitational potential due to this at the center of the square is?? i wonder that why isnt the gravitational potential not cancelling acc to princip of superposition and also what does the negative sign in the answer imply?? pls reply fast

Discussion

46.	If the number of turns in armature is made twice current 3 times and B - 4 times and area of armature is made half then speed of the motor becomes
Answer» If the number of turns in armature is made twice current 3 times and B - 4 times and area of armature is made half then speed of the motor becomes

Discussion

47.	In the following circuit a 10 m long potentiometer wire with resistance 1.2 ohm/m, a resistance R1 and an accumulator of emf 2 V are connected in series. When the emf of thermocouple is 2.4 mV then the deflection in galvanometer is zero. The current supplied by the accumulator will be
Answer» In the following circuit a 10 m long potentiometer wire with resistance 1.2 ohm/m, a resistance R₁ and an accumulator of emf 2 V are connected in series. When the emf of thermocouple is 2.4 mV then the deflection in galvanometer is zero. The current supplied by the accumulator will be

Discussion

48.	A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C = velocity of light)
Answer» A radiation of energy $E$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is ( $C$ = velocity of light)

Discussion

49.	Figure shows a tube structure in which a sound signal is sent from one end and is received at the other end. The semicircular part has a radius of 10.0 cm. The frequency of the sound source can be varied electronically between 1000 Hz and 4000 Hz. Find the approximate frequency(s) at which a maxima of intensity is detected. [The speed of sound in air = 340 ms−1]
Answer» Figure shows a tube structure in which a sound signal is sent from one end and is received at the other end. The semicircular part has a radius of $10.0 cm$ . The frequency of the sound source can be varied electronically between $1000 Hz$ and $4000 Hz$ . Find the approximate frequency(s) at which a maxima of intensity is detected. [The speed of sound in air = $340 {ms}^{- 1}$ ]

Discussion

50.	The acute angle between two lines →r=2^i−5^j+^k+α(3^i+2^j+6^k) and →r=7^i−6^j+^k+β(^i+2^j+2^k) is
Answer» The acute angle between two lines $\to r = 2^i - 5^j +^k + α (3^i + 2^j + 6^k) a n d \to r = 7^i - 6^j +^k + β (^i + 2^j + 2^k)$ is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

What is trajectory?

Akash placed a candle in front of a convex lens and obtained an image as shown below. Now he covered the upper half of the lens with a black paper. What can you say about the image formed?

A current-carrying circular coil of 100 turns and radius 5.0 cm produces a magnetic field of 6.0×10−5 T at its centre. Find the value of the current.

For a satellite escape velocity is 11 km / s. If the satellite is launched at an angle of 60∘ with the vertical, then escape velocity will be

What are the common barriers to effective communication? Suggest measures to overcome them.

Which of the following is paramagnetic

A combination of secondary cells has an equivalent EMF of 2 V. Due to long use they have a large equivalent resistance of 400 Ω. What maximum current can be drawn?

With increase in temperature, the resistivity of a semiconductor?

The horizontal range of an oblique projectile is equal to the distance through which a projectile has to fall freely from rest to acquire a velocity equal to the velocity of projection in magnitude. The angle of projection is

If CP and CV denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then

When the temperature of a black body increase by 0.1%, the wavelength corresponding to maximum emission changes by 0.13 μm. The initial wavelength corresponding to maximum emission is

Both the strings, shown in figure, are made of same material and have same cross section. The pulleys are light. The wave speed of a transverse wave in the string AB is v1 and in CD it is v2. The v1v2 is

Voltage of modulating wave of 5 V with 10 MHz frequency, was superimposed on carrier wave of frequency 20 MHz & 20 V, then the modulation index is given by 1/x. Find x.

The displacement x of a particle varies with time t as x=A sin2 ωt+B cos2 ωt+C sin ωt cos ωt For what values of A, B and C is the motion simple harmonic?

A man of mass M=50 kg stands at one end of the boat which is floating on still water. The man walks to the other end of the boat. Length of the boat is L=10 m and mass M′=100 kg. Then find the distance moved by the boat relative to the ground

An electron is accelerated through a potential difference of 1000 volt. The velocity acquired by the electron is

Two large parallel metallic plates are given charge Q and 2Q as shown in figure. Which graph show variation of electric field as a function of x. [Take ideal condition]

A stretched rope having linear mass density 5×10−2kgm−1 is under a tension of 80N. Power (in Watts) =648nπ2×10−2 has to be supplied to the rope to generate harmonic waves at a frequency of 60Hz and an amplitude of 6 cm. The value of n is___

A hydrogen atom in its ground state is irradiated by light of wavelength 970 ˚A. Taking hce=1.237×10−6 eV and the ground state energy of hydrogen atom as −13.6 eV, the number of lines present in the emission spectrum is

A coil of resistance 20 Ω and inductance 5 H has been connected to a 100 V battery and the switch is closed at t=0. After how much time will the current acquire half of its steady state value. (ln2=0.693)

Unit vector perpendicular to both→A and →B is

How to derive the kinematic equations?

A string is stretched between fixed points separated by 40 cm. It is observed to have consecutive resonant frequencies of 340 Hz and 510 Hz. Then, find the speed of wave on the string.

Water flows through a horizontal pipe with a cross-sectional area of 2 m2 at a speed of 5 m/s with a pressure of 3×105 Pa at a point A. At point B, the cross-sectional area is 1 m2. Calculate the pressure at point B.

If →a&amp;→b are unit vectors, then angle between →a and →b for √3→a−→b to be unit vector is

Why shockers used in scooters and cars?

The ratio of time taken by a body to slide down a smooth surface to rough identical inclined surface of angle θ is ‘n′. Find the coefficient of friction.

Evaluate the integrals using substitution. ∫10xx2+1dx.

A vessel contains 14 g of hydrogen and 96 g of oxygen at STP. Chemical reaction is induced by passing electric spark in the vessel till one of the gases is consumed. The temperature is brought back to its starting value 273 K. Find the pressure in the vessel.

Why we multiply 10-9 with wavelength,?

The heat generated in a circuit is dependent upon the resistance, current and time for which the current is flown. if the error in measuring the above are 1% , 2% and 1% respectively than what will be the maximum error in measuring the heat

A string can sustain a maximum force of 200 N without breaking. A block of mass of 1 kg is tied to one end of the string of 2 m long and the mass is rotated in a horizontal circular path. The maximum linear speed of mass is (in m/s).

An amount of charge Q is distributed between two particles. What should be the charges of the two particles so that the force of interaction between them is maximum?

The vapour density of a mixture containing NO2 and N2O4 is 38.3 at 27'C. Calculate moles of NO2 in 100 g of mixture.

two electrons held at distance r are released from rest . maximum kinetic energy obtained by electron is _. Options are A. Zero B.ke^2/r C.ke^2/2r D.ke^2/r^2

Two balls of masses 2 kg and 5 kg moving on a frictionless surface, collide head-on with speeds 2 m/s and 3 m/s as shown in figure. If the coefficient of restitution is 0.25, then the kinetic energy lost by the balls is

A rectangular lamina of mass 6 kg, breadth 4 m and length 6 m is taken as shown in figure. If Ix and Iy are the moments of inertia of the rectangular lamina about x− axis and y− axis respectively, then the value Iy+Ix is

Along an infinitely long conductor carrying a current of 8 A we keep another conductor of length 5 m carrying a current of 3 A. Both the conductors are 10 cm apart. Find the force on small conductor.

If the number of turns in armature is made twice current 3 times and B - 4 times and area of armature is made half then speed of the motor becomes

In the following circuit a 10 m long potentiometer wire with resistance 1.2 ohm/m, a resistance R1 and an accumulator of emf 2 V are connected in series. When the emf of thermocouple is 2.4 mV then the deflection in galvanometer is zero. The current supplied by the accumulator will be

A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C = velocity of light)

The acute angle between two lines →r=2^i−5^j+^k+α(3^i+2^j+6^k) and →r=7^i−6^j+^k+β(^i+2^j+2^k) is

If →a&→b are unit vectors, then angle between →a and →b for √3→a−→b to be unit vector is