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201.

Find component of vector →A along the direction of →B i.e. A||B and in perpendicular direction of →B that is A⊥B.

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Find component of vector A along the direction of B i.e. A||B and in perpendicular direction of B that is AB.



202.

The speed of light c, gravitational constant G and planck’s constant h are taken as fundamental units in a system. The dimensions of time in this new system should be

Answer»

The speed of light c, gravitational constant G and planck’s constant h are taken as fundamental units in a system. The dimensions of time in this new system should be

203.

Between the plates of parallel plate capacitor of capacitance C, two parallel plates, of the same material and area same as per the plate of the original capacitor, are placed. If the thickness of these plates is equal to 15th of the distance between the plates of the original capacitor, then the capacitance of the new capacitor is

Answer»

Between the plates of parallel plate capacitor of capacitance C, two parallel plates, of the same material and area same as per the plate of the original capacitor, are placed. If the thickness of these plates is equal to 15th of the distance between the plates of the original capacitor, then the capacitance of the new capacitor is



204.

In the given figure, the velocity v3 will be

Answer»

In the given figure, the velocity v3 will be


205.

A particle is executing a simple harmonic motion. Its maximum acceleration is α and maximum velocity is β. Then, its time period of vibration will be

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A particle is executing a simple harmonic motion. Its maximum acceleration is α and maximum velocity is β. Then, its time period of vibration will be

206.

Three blocks of mass 2 kg,3 kg and 5 kg are tied with three identical strings. The blocks are free to rotate in a vertical circle. The minimum velocity given to the blocks to complete the vertical circle is v1, v2 and v3 respectively then

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Three blocks of mass 2 kg,3 kg and 5 kg are tied with three identical strings. The blocks are free to rotate in a vertical circle. The minimum velocity given to the blocks to complete the vertical circle is v1, v2 and v3 respectively then

207.

Two vectors →A and →B have magnitude 3 each. If →A×→B=−5^k+2^i, then the angle between A and B is

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Two vectors A and B have magnitude 3 each. If A×B=5^k+2^i, then the angle between A and B is

208.

A ball is thrown up from the top of a tower at 20 m/s velocity. It took the ball 6 sec to fall to the bottom. How high is the tower?

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A ball is thrown up from the top of a tower at 20 m/s velocity. It took the ball 6 sec to fall to the bottom. How high is the tower?



209.

Light of wavelength λ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to λ′ where

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Light of wavelength λ strikes a photo-sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is to be increased to 2E, the wavelength must be changed to λ where



210.

The unit of momentum is

Answer»

The unit of momentum is

211.

The potential energy (in joule) of a body of mass 2 kg moving in the x−y plane is given by U=6x+8y, where the position coordinates x and y are measured in meter. If the body is at rest at point (6m,4m) at time t=0, it will cross the y – axis at time t equal to

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The potential energy (in joule) of a body of mass 2 kg moving in the xy plane is given by U=6x+8y, where the position coordinates x and y are measured in meter. If the body is at rest at point (6m,4m) at time t=0, it will cross the y – axis at time t equal to

212.

Two objects are thrown up at angles of 45∘ and 60∘ respectively, with the horizontal. If both objects attain same vertical height, then the ratio of magnitude of velocities with which they are projected is

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Two objects are thrown up at angles of 45 and 60 respectively, with the horizontal. If both objects attain same vertical height, then the ratio of magnitude of velocities with which they are projected is

213.

Two masses m1=5 kg and m2=10 kg connected by an inextensible string over a frictionless pulley, as shown in the figure are moving . The coefficient of friction of horizontal surface is 0.15. The minimum weight m that should be put on top of m2 to stop the motion is

Answer»

Two masses m1=5 kg and m2=10 kg connected by an inextensible string over a frictionless pulley, as shown in the figure are moving . The coefficient of friction of horizontal surface is 0.15. The minimum weight m that should be put on top of m2 to stop the motion is




214.

Two equal forces(F) have their resultant equal to either of the forces. Then, at what angle the forces are inclined?

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Two equal forces(F) have their resultant equal to either of the forces. Then, at what angle the forces are inclined?

215.

A 800 kg car takes a circular turn of radius 25 m with an uniform speed of 36 km/h. The centripetal force acting upon the car is

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A 800 kg car takes a circular turn of radius 25 m with an uniform speed of 36 km/h. The centripetal force acting upon the car is

216.

A long spring is stretched by 2 cm. Its potential energy is U. If the spring is stretched by 10 cm, its potential energy would be

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A long spring is stretched by 2 cm. Its potential energy is U. If the spring is stretched by 10 cm, its potential energy would be

217.

A geostationary satellite

Answer»

A geostationary satellite



218.

The energy that should be added to an electron to reduce its de Broglie wavelength from one nm to 0.5 nm is

Answer»

The energy that should be added to an electron to reduce its de Broglie wavelength from one nm to 0.5 nm is



219.

A rope of mass 5 kg is moving vertically with an upward force of 100 N acting at the upper end and a downward force of 70 N acting at the lower end. The tension at the midpoint of the rope is (Take g=10 m/s2)

Answer»

A rope of mass 5 kg is moving vertically with an upward force of 100 N acting at the upper end and a downward force of 70 N acting at the lower end. The tension at the midpoint of the rope is

(Take g=10 m/s2)


220.

The position of centre of mass of a system consisting of two particles of masses m1 and m2 separated by a distance L apart, from m1 will be

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The position of centre of mass of a system consisting of two particles of masses m1 and m2 separated by a distance L apart, from m1 will be

221.

Flux due to q through square plate is

Answer»

Flux due to q through square plate is


222.

The kinetic energy of the electron in an orbit of radius r in hydrogen atom is (e = electronic charge)

Answer» The kinetic energy of the electron in an orbit of radius r in hydrogen atom is (e = electronic charge)
223.

A body of mass m=5 kg is thrown at an angle θ=30∘ to the horizontal with the initial velocity v0=20 m/s. Assuming the air drag to be negligible, find the magnitude of the momentum increment Δp during the total time of motion.

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A body of mass m=5 kg is thrown at an angle θ=30 to the horizontal with the initial velocity v0=20 m/s. Assuming the air drag to be negligible, find the magnitude of the momentum increment Δp during the total time of motion.




224.

Thermal coefficient of volume expansion at constant pressure for an ideal gas sample of n moles having pressure Po, volume Vo and temperature To is:

Answer»

Thermal coefficient of volume expansion at constant pressure for an ideal gas sample of n moles having pressure Po, volume Vo and temperature To is:

225.

The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to

Answer» The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to
226.

If velocity v, force F and energy E are taken as fundmental units, then dimensional formula for mass will be

Answer»

If velocity v, force F and energy E are taken as fundmental units, then dimensional formula for mass will be

227.

Consider a special situtation in which both the faces of the block M0 are smooth, as shown in adjoining figure. Mark out the correct statement(s)(A) If F=0, the blocks M and m cannot remain stationary (B) For one unique value of F, the blocks M and m remain stationary with respect to block M0(C) There exists a range of F for which blocks M and m remain stationary with respect to block M0(D) Since there is no friction, therefore, blocks M and m cannot be in equillibrium with respect to block M0

Answer»

Consider a special situtation in which both the faces of the block M0 are smooth, as shown in adjoining figure. Mark out the correct statement(s)





(A) If F=0, the blocks M and m cannot remain stationary

(B) For one unique value of F, the blocks M and m remain stationary with respect to block M0

(C) There exists a range of F for which blocks M and m remain stationary with respect to block M0

(D) Since there is no friction, therefore, blocks M and m cannot be in equillibrium with respect to block M0

228.

The elevator shown in fig. is descending with an acceleration of 2 m/s2. The mass of the block A=0.5 kg and that of B=1 kg. The force exerted by the block A on block B is

Answer»

The elevator shown in fig. is descending with an acceleration of 2 m/s2. The mass of the block A=0.5 kg and that of B=1 kg. The force exerted by the block A on block B is


229.

Find the maximum value of F such that both the blocks move together. Take g=10 m/s2.

Answer»

Find the maximum value of F such that both the blocks move together. Take g=10 m/s2.


230.

If a block is at rest on an inclined plane, the direction of friction is

Answer» If a block is at rest on an inclined plane, the direction of friction is
231.

A body starts from rest. What will be the ratio of the distance travelled by the body during the 4th and 3rd second?

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A body starts from rest. What will be the ratio of the distance travelled by the body during the 4th and 3rd second?

232.

A prticle of mass m moves with velocity v0=20 m/s towards a large wall that is moving with velocity v=5 m/s towards the particle as shown. If the particle collides with the wall elastically, then find the speed of the particle just after collision. (Assume collision with the wall is elastic)

Answer»

A prticle of mass m moves with velocity v0=20 m/s towards a large wall that is moving with velocity v=5 m/s towards the particle as shown. If the particle collides with the wall elastically, then find the speed of the particle just after collision. (Assume collision with the wall is elastic)




233.

A current I flows through a flat metal specimen of constant thickness and of the shape as shown in the figure. Given that v1,v2 and v3 are mean drift speeds of the electron crossing the sections P1,P2 and P3 respectively. Then

Answer»

A current I flows through a flat metal specimen of constant thickness and of the shape as shown in the figure. Given that v1,v2 and v3 are mean drift speeds of the electron crossing the sections P1,P2 and P3 respectively. Then


234.

Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant, one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time of

Answer»

Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant, one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time of


235.

Two particles having masses m1 and m2 are situated in a plane perpendicular to line AB at a distance of r1and r2 respectively as shown.Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining m1 and m2

Answer»

Two particles having masses m1 and m2 are situated in a plane perpendicular to line AB at a distance of r1and r2 respectively as shown.


Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining m1 and m2




236.

If W1, W2 and W3 represents the work done in moving a particle from A to B along three different paths 1, 2 and 3, respectively (as shown) in the gravitational field of a point mass m, find the correct relation between W1, W2 and W3.

Answer» If W1, W2 and W3 represents the work done in moving a particle from A to B along three different paths 1, 2 and 3, respectively (as shown) in the gravitational field of a point mass m, find the correct relation between W1, W2 and W3.


237.

A man running on a horizontal road at 8 ms−1 finds rain falling vertically. If he increases his speed to 12 ms−1, he finds that drops make 30∘ angle with the vertical. Find the velocity of rain with respect to the road.

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A man running on a horizontal road at 8 ms1 finds rain falling vertically. If he increases his speed to 12 ms1, he finds that drops make 30 angle with the vertical. Find the velocity of rain with respect to the road.

238.

Arrangement of two block system is as shown. The net force acting on 1 kg and 2 kg blocks are (assuming the surfaces to be frictionless) respectively.

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Arrangement of two block system is as shown. The net force acting on 1 kg and 2 kg blocks are (assuming the surfaces to be frictionless) respectively.


239.

Internal resistance of a 2.1 V cell which gives a current of 0.2 A through an external resistance of 10 Ω is

Answer»

Internal resistance of a 2.1 V cell which gives a current of 0.2 A through an external resistance of 10 Ω is

240.

A car travels with the speed of 15 m/s for 0<t≤5 sec, 20 m/s for 5<t≤10 sec and 5 m/s for 10<t≤15 sec. The total distance travelled by the car is

Answer»

A car travels with the speed of 15 m/s for 0<t5 sec, 20 m/s for 5<t10 sec and 5 m/s for 10<t15 sec. The total distance travelled by the car is

241.

A pulley system is connected as shown in the figure. If the spring is elongated by a distance of 0.02 m, then what is the force constant of the spring? (Assume that the spring does not affect the overall acceleration of the bodies.)

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A pulley system is connected as shown in the figure. If the spring is elongated by a distance of 0.02 m, then what is the force constant of the spring? (Assume that the spring does not affect the overall acceleration of the bodies.)




242.

A particle starting from rest undergoes acceleration given by a=|t–2| m/s2 where, t is time in second. Velocity of particle after 4 sec is

Answer»

A particle starting from rest undergoes acceleration given by a=|t2| m/s2 where, t is time in second. Velocity of particle after 4 sec is

243.

In an L–R circuit L=0.4Hπ and R = 30 Ω If the circuit has an alternating emf of 220 volt and its frequency 50 cycles per sec, the impendence and current in the circuit respectively will be

Answer»

In an L–R circuit L=0.4Hπ and R = 30 Ω If the circuit has an alternating emf of 220 volt and its frequency 50 cycles per sec, the impendence and current in the circuit respectively will be

244.

Water from a tap emerges vertically downwards with an initial speed of 1 m/s. The cross-section area of the tap is 10−4 m2 . Assuming that the pressure is constant throughout the stream of water and the flow is steady, what will be the cross-section area of the stream 0.15 m below the tap?

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Water from a tap emerges vertically downwards with an initial speed of 1 m/s. The cross-section area of the tap is 104 m2 . Assuming that the pressure is constant throughout the stream of water and the flow is steady, what will be the cross-section area of the stream 0.15 m below the tap?

245.

Three point masses M1=1.6 kg,M2=2.4 kg and M3=2 kg are placed at the corners of a thin massless rectangular sheet (1.2 m×1.0 m) as shown in the figure below. Centre of mass of the system will be located at a point (assuming M1 to be at the origin)

Answer»

Three point masses M1=1.6 kg,M2=2.4 kg and M3=2 kg are placed at the corners of a thin massless rectangular sheet (1.2 m×1.0 m) as shown in the figure below. Centre of mass of the system will be located at a point (assuming M1 to be at the origin)




246.

When the temperature of a rod increases from t to t+Δt, the moment of inertia of the rod increases from I to I+ΔI. If the coefficient of linear expansion of the rod is α, the ratio ΔII is

Answer»

When the temperature of a rod increases from t to t+Δt, the moment of inertia of the rod increases from I to I+ΔI. If the coefficient of linear expansion of the rod is α, the ratio ΔII is



247.

Find the value of cos(24o)+cos(5o)+cos(175o)+cos(204o)+cos(300o).

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Find the value of cos(24o)+cos(5o)+cos(175o)+cos(204o)+cos(300o).

248.

The pulley arrangements of figures (a) and (b) are identical. The mass of the rope is negligible. In Fig. (a), the mass m is lifted up by attaching a mass 2m to the other end of the rope. In Fig. (b) , m is lifted up by pulling the other end of the rope with a constant downward force F=2mg. The acceleration of m is the same in both cases.

Answer»

The pulley arrangements of figures (a) and (b) are identical. The mass of the rope is negligible. In Fig. (a), the mass m is lifted up by attaching a mass 2m to the other end of the rope. In Fig. (b) , m is lifted up by pulling the other end of the rope with a constant downward force F=2mg. The acceleration of m is the same in both cases.



249.

A block of mass m is kept on the floor of a freely falling lift. During the free fall of the lift, the block is pulled horizontally with a force of F=5 N. If coefficient of friction between block and floor is μs=0.1, then the frictional force on the block will be

Answer»

A block of mass m is kept on the floor of a freely falling lift. During the free fall of the lift, the block is pulled horizontally with a force of F=5 N. If coefficient of friction between block and floor is μs=0.1, then the frictional force on the block will be


250.

Dimensional formula for intensity of magnetising field and magnetic susceptibility are.

Answer»

Dimensional formula for intensity of magnetising field and magnetic susceptibility are.