50278 + Interview Questions in Physics Page 38 InterviewSolution

1851.	The switch S in the circuit shown is closed. If the value of potential at A is 20 V , then the value of current i will be (Give integer value)
Answer» The switch $S$ in the circuit shown is closed. If the value of potential at $A$ is $20 V$ , then the value of current $i$ will be (Give integer value)

Discussion

1852.	A circuit contains two inductors of self-inductance L1 and L2 in series (see figure). If M is the mutual inductance, then the effective inductance of the circuit shown will be
Answer» A circuit contains two inductors of self-inductance $L_{1}$ and $L_{2}$ in series (see figure). If $M$ is the mutual inductance, then the effective inductance of the circuit shown will be

Discussion

1853.	99. A particle moving with uniform speed v , changes its direction by angle theta in time t. Magnitude of its average acceleration during this time is
Answer» 99. A particle moving with uniform speed v , changes its direction by angle theta in time t. Magnitude of its average acceleration during this time is

Discussion

1854.

A charged particle (electron or proton) is introduced at the origin (x=0,y=0,x=0) with a given initial velocity →v. A uniform electric field →E and a uniform magnetic field →B exist everywhere. The velocity →v, electric field →E and magnetic field →B are given in column 1,2 and 3, respectively. The quantities E0, B0 are positive in magnitude.Column 1Column 2Column 3(I) Electron with →v=2E0B0^x(i) →E=E0^z(P) →B=−B0^x(II) Electron with →v=E0B0^y(ii) →E=−E0^y(Q) →B=−B0^x(III) Electron with →v=0(iii) →E=−E0^x(R) →B=B0^y(IV) Electron with →v=2E0B0^x(iv) →E=E0^x(S) →B=B0^z In which case will the particle move in a straight line with constant velocity?

Answer»

A charged particle (electron or proton) is introduced at the origin $(x = 0, y = 0, x = 0)$ with a given initial velocity $\to v$ . A uniform electric field $\to E$ and a uniform magnetic field $\to B$ exist everywhere. The velocity $\to v$ , electric field $\to E$ and magnetic field $\to B$ are given in column $1, 2$ and $3,$ respectively. The quantities $E_{0}, B_{0}$ are positive in magnitude.

Column 1	Column 2	Column 3
$(I)$ Electron with $\to v = 2 \frac{E_{0}}{B_{0}}^x$	$(i)$ $\to E = E_{0}^z$	$(P)$ $\to B = - B_{0}^x$
$(I I)$ Electron with $\to v = \frac{E_{0}}{B_{0}}^y$	$(i i)$ $\to E = - E_{0}^y$	$(Q)$ $\to B = - B_{0}^x$
$(I I I)$ Electron with $\to v = 0$	$(i i i)$ $\to E = - E_{0}^x$	$(R)$ $\to B = B_{0}^y$
$(I V)$ Electron with $\to v = 2 \frac{E_{0}}{B_{0}}^x$	$(i v)$ $\to E = E_{0}^x$	$(S)$ $\to B = B_{0}^z$

In which case will the particle move in a straight line with constant velocity?

Discussion

1855.	140 Three sources of light A, B and C produce intensities 4I , 9I and 16I at a point P when they are switched on independently. Light from A and B are coherent and have a phase difference pi / 3 at the point P while source C, emitting at same frequency, is in coherent.The total intensity at P
Answer» 140 Three sources of light A, B and C produce intensities 4I , 9I and 16I at a point P when they are switched on independently. Light from A and B are coherent and have a phase difference pi / 3 at the point P while source C, emitting at same frequency, is in coherent.The total intensity at P

Discussion

1856.	Is a vector necessarily changed if it is rotated through an angle?
Answer» Is a vector necessarily changed if it is rotated through an angle?

Discussion

1857.	when 2 bodies move uniformly towards echother , the distance between them decreases by 4m/s. If both the bodies move in the same direction , with the same speeds , the distance between them increases by 2/s. What are the speeds of the 2 bodies
Answer» when 2 bodies move uniformly towards echother , the distance between them decreases by 4m/s. If both the bodies move in the same direction , with the same speeds , the distance between them increases by 2/s. What are the speeds of the 2 bodies

Discussion

1858.	A block of mass m, lying on a smooth horizontal surface, is attached to a spring (of negligible mass) of spring constant k. The other end of the spring is fixed, as shown in the figure. The block is initially at rest in its equilibrium position. If now the block is pulled with a constant force F, the maximum speed of the block is:
Answer» A block of mass $m$ , lying on a smooth horizontal surface, is attached to a spring (of negligible mass) of spring constant $k$ . The other end of the spring is fixed, as shown in the figure. The block is initially at rest in its equilibrium position. If now the block is pulled with a constant force $F$ , the maximum speed of the block is:

Discussion

1859.	For an ideal gas expanding adiabatically in vacuum:
Answer» For an ideal gas expanding adiabatically in vacuum:

Discussion

1860.	the amplitude of the simple harmonic motion is Y=(3 sin omega t+4 cos omega t)m
Answer» the amplitude of the simple harmonic motion is Y=(3 sin omega t+4 cos omega t)m

Discussion

1861.	A compond microscope having F(o) = 7mm and F(e) = 20mm and distance between the lenses is 20 cm . if image is formed at least distance of distinct vision then magnifying power ? 1) 337 2) 400 3) 220 4) 120
Answer» A compond microscope having F(o) = 7mm and F(e) = 20mm and distance between the lenses is 20 cm . if image is formed at least distance of distinct vision then magnifying power ? 1) 337 2) 400 3) 220 4) 120

Discussion

1862.	A spherical ball of radius 3×10−4m and density 104kg/m3 falls freely under the gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball doesn’t change, find h. [Viscosity of water=9.8×10−6N−s/m2 and g=9.8m/s2]
Answer» A spherical ball of radius $3 \times 10^{- 4} m$ and density $10^{4} k g / m^{3}$ falls freely under the gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball doesn’t change, find h. $[V i s c o s i t y o f w a t e r = 9.8 \times 10^{- 6} N - s / m^{2} a n d g = 9.8 m / s^{2}]$

1862.

A spherical ball of radius 3×10−4m and density 104kg/m3 falls freely under the gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball doesn’t change, find h. [Viscosity of water=9.8×10−6N−s/m2 and g=9.8m/s2]

Answer»

A spherical ball of radius $3 \times 10^{- 4} m$ and density $10^{4} k g / m^{3}$ falls freely under the gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball doesn’t change, find h.

$[V i s c o s i t y o f w a t e r = 9.8 \times 10^{- 6} N - s / m^{2} a n d g = 9.8 m / s^{2}]$

Discussion

1863.	A rifle shoots a bullet from the ground level with a muzzle velocity of 400 m/s at a small target 400 m away on the ground. The height above the target at which the bullet must be aimed to hit the target is (g=10 ms−2)
Answer» A rifle shoots a bullet from the ground level with a muzzle velocity of $400 m/s$ at a small target $400 m$ away on the ground. The height above the target at which the bullet must be aimed to hit the target is $(g = 10 {ms}^{- 2})$

Discussion

1864.	Consider a planet as big as Earth but entirely made up of water. Assume the variation in density as negligible, what can be said about the pressure at its centre?
Answer» Consider a planet as big as Earth but entirely made up of water. Assume the variation in density as negligible, what can be said about the pressure at its centre?

Discussion

1865.	If Kinetic energy of body increases by 300%, What will be %age of linear momentum?
Answer» If Kinetic energy of body increases by $300 %$ , What will be $%$ age of linear momentum?

Discussion

1866.	A wire is bent into three segments, each of radius r. Each segment is a quadrant of a circle. The first segment lies in xy− plane, the second in yz−plane and the third in xz−plane. The centre of each quadrant is at origin. If a current I flows through each quadrant, the net magnetic field at origin will be
Answer» A wire is bent into three segments, each of radius $r$ . Each segment is a quadrant of a circle. The first segment lies in $x y -$ plane, the second in $y z -$ plane and the third in $x z -$ plane. The centre of each quadrant is at origin. If a current $I$ flows through each quadrant, the net magnetic field at origin will be

Discussion

1867.	Using differentials, find the approximate value of the following up to 3 places of decimal. (0.0037)12
Answer» Using differentials, find the approximate value of the following up to 3 places of decimal. $(0.0037)^{\frac{1}{2}}$

Discussion

1868.	A person standing on a road sends a sound signal to the driver of a car going away from him at a speed of 72 km h−1. The signal travelling at 330 m s−1 in air and having a frequency of 1600 Hz gets reflected from + body of the car and returns. Find the frequency of reflected signal as heard by the person.
Answer» A person standing on a road sends a sound signal to the driver of a car going away from him at a speed of 72 km $h^{- 1}$ . The signal travelling at 330 m $s^{- 1}$ in air and having a frequency of 1600 Hz gets reflected from + body of the car and returns. Find the frequency of reflected signal as heard by the person.

Discussion

1869.	In a long cylindrical wire of radius R, magnetic induction varies with the distance r from axis as B=Crα, where C & α are constant. Find the function of current density in wire with the distance from the axis of wire.
Answer» In a long cylindrical wire of radius $R$ , magnetic induction varies with the distance $r$ from axis as $B = C r^{α}$ , where $C & α$ are constant. Find the function of current density in wire with the distance from the axis of wire.

Discussion

1870.	Newton's second law of motion relates
Answer» Newton's second law of motion relates

1870.

Newton's second law of motion relates

Answer»

Newton's second law of motion relates

Discussion

1871.	A man uses a concave mirror for shaving. He keeps his face at a distance of 25 cm from the mirror and gets an image which is 1.4 times enlarged. Find the focal length of the mirror.
Answer» A man uses a concave mirror for shaving. He keeps his face at a distance of 25 cm from the mirror and gets an image which is 1.4 times enlarged. Find the focal length of the mirror.

Discussion

1872.	The maximum permissible duration between two samples of 5 kHz signal to ensure perfect reconstruction of the signal is
Answer» The maximum permissible duration between two samples of 5 kHz signal to ensure perfect reconstruction of the signal is

Discussion

1873.	Figure 5.18 shows a man standing stationary with respect to a horizontal conveyor belt that is accelerating with 1 ms−2. What is the net force on the man? If the coefficient of static friction between the man's shoes and the belt is 0.2, up to what acceleration of the belt can the man continue to be stationary relative to the belt? (Mass of the man = 65 kg.)
Answer» Figure 5.18 shows a man standing stationary with respect to a horizontal conveyor belt that is accelerating with $1 m s^{- 2}$ . What is the net force on the man? If the coefficient of static friction between the man's shoes and the belt is 0.2, up to what acceleration of the belt can the man continue to be stationary relative to the belt? (Mass of the man = 65 kg.)

Discussion

1874.	If the ratio of magnetic fields on the axial line of a long magnet at distances of 10 cm and 20 cm is 12.5:1, then the length of the magnet will be
Answer» If the ratio of magnetic fields on the axial line of a long magnet at distances of $10 cm$ and $20 cm$ is $12.5 : 1$ , then the length of the magnet will be

Discussion

1875.	A rolling disc having linear acceleration a and angular acceleration α is placed on a moving surface. The surface is moving with acceleration as, as shown in the image. The disc will be in pure rolling, when
Answer» A rolling disc having linear acceleration $a$ and angular acceleration $α$ is placed on a moving surface. The surface is moving with acceleration $a_{s}$ , as shown in the image. The disc will be in pure rolling, when

Discussion

1876.	The current in a certain circuit varies with time, as shown in the figure. Find the average current from t=0 to t=2 s.
Answer» The current in a certain circuit varies with time, as shown in the figure. Find the average current from $t = 0$ to $t = 2 s$ .

Discussion

1877.	Question 1When will you say a body is in (i) uniform acceleration? (ii) non-uniform acceleration?
Answer» Question 1 When will you say a body is in (i) uniform acceleration? (ii) non-uniform acceleration?

Discussion

1878.	A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 kmph. Its velocity is slowed down to 18 kmph in 4 s by an unbalanced external force. Calculate the magnitude of the force required.
Answer» A motorcar of mass $1200 k g$ is moving along a straight line with a uniform velocity of $90 k m p h$ . Its velocity is slowed down to $18 k m p h$ in $4 s$ by an unbalanced external force. Calculate the magnitude of the force required.

Discussion

1879.	Find the angle of deviation suffered by the light ray shown in figure. The refractive index μ=1.5 for the prism material.
Answer» Find the angle of deviation suffered by the light ray shown in figure. The refractive index $μ = 1.5$ for the prism material.

1879.

Find the angle of deviation suffered by the light ray shown in figure. The refractive index μ=1.5 for the prism material.

Answer»

Find the angle of deviation suffered by the light ray shown in figure. The refractive index $μ = 1.5$ for the prism material.

Discussion

1880.	A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in the figure. The lowest frequency with which the heavy string resonates is 120 Hz. If the movable support is pushed to the right by 10 cm so that the joint is placed on the pulley then the minimum frequency at which the heavy string can resonate will be
Answer» A heavy string is tied at one end to a movable support and to a light thread at the other end as shown in the figure. The lowest frequency with which the heavy string resonates is $120 Hz$ . If the movable support is pushed to the right by $10 cm$ so that the joint is placed on the pulley then the minimum frequency at which the heavy string can resonate will be

Discussion

1881.	The potential energy of a system increases if work is done(1) Upon the system by a conservative force(2) Upon the system by a non conservative force(3) By the system against a conservative force(4) By the system against a non conservative force
Answer» The potential energy of a system increases if work is done(1) Upon the system by a conservative force(2) Upon the system by a non conservative force(3) By the system against a conservative force(4) By the system against a non conservative force

Discussion

1882.	If the electric potential along a line due to a charge is given by V(r)=25r+3, where r is the distance from the charge, what is the electric field at a point r = 5 along this line?
Answer» If the electric potential along a line due to a charge is given by $V (r) = \frac{25}{r} + 3$ , where r is the distance from the charge, what is the electric field at a point r = 5 along this line?

Discussion

1883.	State why transverse Waves cannot propagate through gaseous medium.
Answer» State why transverse Waves cannot propagate through gaseous medium.

Discussion

1884.	A current of 5A is flowing at 220V in the primary coil of a transformer. If the voltage produced in the secondary coil is 220V and 50% of power is lost, then the current in secondary will be:
Answer» A current of 5A is flowing at 220V in the primary coil of a transformer. If the voltage produced in the secondary coil is 220V and 50% of power is lost, then the current in secondary will be:

Discussion

1885.	How to obtain maixma and minima in single slit diffraction and path difference?
Answer» How to obtain maixma and minima in single slit diffraction and path difference?

Discussion

1886.	A Doppler shift ultrasonic flow meter uses two piezoelectric crystals each having a natural frequency of 5 MHz. These crystals are used as transmitter and receiver. The transmitter directs an ultrasonic wave into the pipe which makes an angle of 45∘ with the direction of flow calculate the received frequency (MHz) for a fluid velocity of 20 m/sec. Assume the velocity of sound in fluid to be 500 m/sec. 4.717
Answer» A Doppler shift ultrasonic flow meter uses two piezoelectric crystals each having a natural frequency of 5 MHz. These crystals are used as transmitter and receiver. The transmitter directs an ultrasonic wave into the pipe which makes an angle of $45^{\circ}$ with the direction of flow calculate the received frequency (MHz) for a fluid velocity of 20 m/sec. Assume the velocity of sound in fluid to be 500 m/sec. 4.717

Discussion

1887.	A body of mass 'm' moving with a constant velocity 'v' hits another body of the same mass moving with the same velocity 'v' but in the opposite direction and sticks to it. The velocity of the compound body after collision is
Answer» A body of mass 'm' moving with a constant velocity 'v' hits another body of the same mass moving with the same velocity 'v' but in the opposite direction and sticks to it. The velocity of the compound body after collision is

1887.

A body of mass 'm' moving with a constant velocity 'v' hits another body of the same mass moving with the same velocity 'v' but in the opposite direction and sticks to it. The velocity of the compound body after collision is

Answer»

A body of mass 'm' moving with a constant velocity 'v' hits another body of the same mass moving with the same velocity 'v' but in the opposite direction and sticks to it. The velocity of the compound body after collision is

Discussion

1888.	The force responsible for moon revolving around earth is
Answer» The force responsible for moon revolving around earth is

Discussion

1889.	A slider crank mechanism with crank radius 200 mm and connecting rod length 800 mm is shown. The crank is rotating at 600 rpm in the counter clockwise direction. In the configuration shown, the crank makes an angle of 90o with the sliding direction of the slider, and a force of 5 kN is acting on the slider. Neglecting the inertia forces, the turning moment on the crank (in kNm) is
Answer» A slider crank mechanism with crank radius 200 mm and connecting rod length 800 mm is shown. The crank is rotating at 600 rpm in the counter clockwise direction. In the configuration shown, the crank makes an angle of $90^{o}$ with the sliding direction of the slider, and a force of 5 kN is acting on the slider. Neglecting the inertia forces, the turning moment on the crank (in kNm) is

Discussion

1890.	A thin semicircular conducting ring of radius r is falling with its plane verticle in a horizontal magnetic field B as shown. The potential difference developed across the ring when its speed is v is
Answer» A thin semicircular conducting ring of radius r is falling with its plane verticle in a horizontal magnetic field B as shown. The potential difference developed across the ring when its speed is v is

Discussion

1891.	what is 1. thermal equilibrium 2. internal energy 3. isothermal process 4.adiabatic process 5. isochoric process 6. isobaric process 7. cyclic process 8. calvien plank law 9.claousius law 10. reversible process 11. irreversible process 12. heat engine 13.carnot's engine 14. refrigerator 15. thermodynamics
Answer» what is 1. thermal equilibrium 2. internal energy 3. isothermal process 4.adiabatic process 5. isochoric process 6. isobaric process 7. cyclic process 8. calvien plank law 9.claousius law 10. reversible process 11. irreversible process 12. heat engine 13.carnot's engine 14. refrigerator 15. thermodynamics

Discussion

1892.	The torque provided by an engine is given by T(θ)=12000+2500sin(2θ)N.m, where θ is the angle turned by the crank from inner dead center. The mean speed of the engine is 200 rpm and it drives a machine that provides a constant resisting torque. If variation of the speed form the mean speed is not to exceed ±0.5% the minimum mass momnet of inertia of the flywheel should bekg.m2 (round off to the nearest integer).
Answer» The torque provided by an engine is given by $T (θ) = 12000 + 2500 s i n (2 θ)$ N.m, where $θ$ is the angle turned by the crank from inner dead center. The mean speed of the engine is 200 rpm and it drives a machine that provides a constant resisting torque. If variation of the speed form the mean speed is not to exceed $\pm 0.5 %$ the minimum mass momnet of inertia of the flywheel should bekg.m $^{2}$ (round off to the nearest integer).

Discussion

1893.	Two identical particles move towards each other with velocity 2v and v respectively. The velocity of the centre of mass is
Answer» Two identical particles move towards each other with velocity 2v and v respectively. The velocity of the centre of mass is

Discussion

1894.	50.The speed of sound waves in air at 300k is 332m/s. At what temperature will the speed be 574m/s?
Answer» 50.The speed of sound waves in air at 300k is 332m/s. At what temperature will the speed be 574m/s?

Discussion

1895.	if the radius of the earth is to decrease by 1%. its mass remaining the same, the acceleration due to gravity on the earth's surface will increase or decrease and by how much percentage?
Answer» if the radius of the earth is to decrease by 1%. its mass remaining the same, the acceleration due to gravity on the earth's surface will increase or decrease and by how much percentage?

Discussion

1896.	The vernier scale of a callipers has 50 divisions which coincide with 49 main scale divisions. If each main scale division is of 0.5mm, then the minimum inaccuracy in the measurement by callipers is (1.) 0.02 cm (2.) 0.02 mm(3.) 0.01 mm (4.) 0.01 cm
Answer» The vernier scale of a callipers has 50 divisions which coincide with 49 main scale divisions. If each main scale division is of 0.5mm, then the minimum inaccuracy in the measurement by callipers is (1.) 0.02 cm (2.) 0.02 mm (3.) 0.01 mm (4.) 0.01 cm

Discussion

1897.	A train travelling at 60 km/h overtakes another train travelling at 42 km/h. Assuming each car to be 50 m long and initially train A to be just behind the train B, the total distance train A will cover to overtake train B is closest to
Answer» A train travelling at $60 km/h$ overtakes another train travelling at $42 km/h$ . Assuming each car to be $50 m$ long and initially train $A$ to be just behind the train $B$ , the total distance train A will cover to overtake train B is closest to

Discussion

1898.	Assumimng new cartesian sign convention, choose the correct option for the Lens shown in figure:
Answer» Assumimng new cartesian sign convention, choose the correct option for the Lens shown in figure:

Discussion

1899.	Find the maximum velocity of photoelectrons emitted by radiation of frequency 3 × 1015 H from a photoelectric surface having work function of 4.0 eV. \lbrack h = 6.6 × 10–34 J-s and me = 9.1 × 10–31 kg\rbrack
Answer» Find the maximum velocity of photoelectrons emitted by radiation of frequency 3 × 1015 H from a photoelectric surface having work function of 4.0 eV. \lbrack h = 6.6 × 10–34 J-s and me = 9.1 × 10–31 kg\rbrack

Discussion

1900.	Airplanes A and B are flying with constant velocity in the same vertical plane at angles 30∘ and 60∘ with respect to the horizontal respectively as shown in the figure. The speed of A is 100√3 m/s. At time t = 0s, an observer in A finds B at a distance of 500m. The observer sees B moving with a constant velocity perpendicular to the line of motion of A. If at t=t0, A just escapes being hit by B,t0 in seconds is .
Answer» Airplanes A and B are flying with constant velocity in the same vertical plane at angles $30^{\circ}$ and $60^{\circ}$ with respect to the horizontal respectively as shown in the figure. The speed of A is $100 \sqrt{3}$ m/s. At time t = 0s, an observer in A finds B at a distance of 500m. The observer sees B moving with a constant velocity perpendicular to the line of motion of A. If at $t = t_{0}$ , A just escapes being hit by $B, t_{0}$ in seconds is .

Discussion

Explore topic-wise InterviewSolutions in .

The switch S in the circuit shown is closed. If the value of potential at A is 20 V , then the value of current i will be (Give integer value)

A circuit contains two inductors of self-inductance L1 and L2 in series (see figure). If M is the mutual inductance, then the effective inductance of the circuit shown will be

99. A particle moving with uniform speed v , changes its direction by angle theta in time t. Magnitude of its average acceleration during this time is

140 Three sources of light A, B and C produce intensities 4I , 9I and 16I at a point P when they are switched on independently. Light from A and B are coherent and have a phase difference pi / 3 at the point P while source C, emitting at same frequency, is in coherent.The total intensity at P

Is a vector necessarily changed if it is rotated through an angle?

when 2 bodies move uniformly towards echother , the distance between them decreases by 4m/s. If both the bodies move in the same direction , with the same speeds , the distance between them increases by 2/s. What are the speeds of the 2 bodies

For an ideal gas expanding adiabatically in vacuum:

the amplitude of the simple harmonic motion is Y=(3 sin omega t+4 cos omega t)m

A compond microscope having F(o) = 7mm and F(e) = 20mm and distance between the lenses is 20 cm . if image is formed at least distance of distinct vision then magnifying power ? 1) 337 2) 400 3) 220 4) 120

A spherical ball of radius 3×10−4m and density 104kg/m3 falls freely under the gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball doesn’t change, find h. [Viscosity of water=9.8×10−6N−s/m2 and g=9.8m/s2]

A rifle shoots a bullet from the ground level with a muzzle velocity of 400 m/s at a small target 400 m away on the ground. The height above the target at which the bullet must be aimed to hit the target is (g=10 ms−2)

Consider a planet as big as Earth but entirely made up of water. Assume the variation in density as negligible, what can be said about the pressure at its centre?

If Kinetic energy of body increases by 300%, What will be %age of linear momentum?

Using differentials, find the approximate value of the following up to 3 places of decimal. (0.0037)12

In a long cylindrical wire of radius R, magnetic induction varies with the distance r from axis as B=Crα, where C &amp; α are constant. Find the function of current density in wire with the distance from the axis of wire.

Newton's second law of motion relates

A man uses a concave mirror for shaving. He keeps his face at a distance of 25 cm from the mirror and gets an image which is 1.4 times enlarged. Find the focal length of the mirror.

The maximum permissible duration between two samples of 5 kHz signal to ensure perfect reconstruction of the signal is

If the ratio of magnetic fields on the axial line of a long magnet at distances of 10 cm and 20 cm is 12.5:1, then the length of the magnet will be

A rolling disc having linear acceleration a and angular acceleration α is placed on a moving surface. The surface is moving with acceleration as, as shown in the image. The disc will be in pure rolling, when

The current in a certain circuit varies with time, as shown in the figure. Find the average current from t=0 to t=2 s.

Question 1When will you say a body is in (i) uniform acceleration? (ii) non-uniform acceleration?

A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 kmph. Its velocity is slowed down to 18 kmph in 4 s by an unbalanced external force. Calculate the magnitude of the force required.

Find the angle of deviation suffered by the light ray shown in figure. The refractive index μ=1.5 for the prism material.

The potential energy of a system increases if work is done(1) Upon the system by a conservative force(2) Upon the system by a non conservative force(3) By the system against a conservative force(4) By the system against a non conservative force

If the electric potential along a line due to a charge is given by V(r)=25r+3, where r is the distance from the charge, what is the electric field at a point r = 5 along this line?

State why transverse Waves cannot propagate through gaseous medium.

A current of 5A is flowing at 220V in the primary coil of a transformer. If the voltage produced in the secondary coil is 220V and 50% of power is lost, then the current in secondary will be:

How to obtain maixma and minima in single slit diffraction and path difference?

A body of mass 'm' moving with a constant velocity 'v' hits another body of the same mass moving with the same velocity 'v' but in the opposite direction and sticks to it. The velocity of the compound body after collision is

The force responsible for moon revolving around earth is

A thin semicircular conducting ring of radius r is falling with its plane verticle in a horizontal magnetic field B as shown. The potential difference developed across the ring when its speed is v is

Two identical particles move towards each other with velocity 2v and v respectively. The velocity of the centre of mass is

50.The speed of sound waves in air at 300k is 332m/s. At what temperature will the speed be 574m/s?

if the radius of the earth is to decrease by 1%. its mass remaining the same, the acceleration due to gravity on the earth's surface will increase or decrease and by how much percentage?

The vernier scale of a callipers has 50 divisions which coincide with 49 main scale divisions. If each main scale division is of 0.5mm, then the minimum inaccuracy in the measurement by callipers is (1.) 0.02 cm (2.) 0.02 mm(3.) 0.01 mm (4.) 0.01 cm

A train travelling at 60 km/h overtakes another train travelling at 42 km/h. Assuming each car to be 50 m long and initially train A to be just behind the train B, the total distance train A will cover to overtake train B is closest to

Assumimng new cartesian sign convention, choose the correct option for the Lens shown in figure:

Find the maximum velocity of photoelectrons emitted by radiation of frequency 3 × 1015 H from a photoelectric surface having work function of 4.0 eV. \lbrack h = 6.6 × 10–34 J-s and me = 9.1 × 10–31 kg\rbrack

In a long cylindrical wire of radius R, magnetic induction varies with the distance r from axis as B=Crα, where C & α are constant. Find the function of current density in wire with the distance from the axis of wire.