Two identical piano wires kept under the same tension T have a fundamental frequency of 600 Hz. The fractional increase in the tension of one of the wires which will lead to occurrence of 6 beats/s when both the wires oscillate together would be
0.02
0.03
0.04
0.04
A coil has resistance 30 O and inductive reactance 20 O at 50 Hz frequency. If an AC source 200 V, 100 Hz, is connected across the coil, the current in the coil will be
4.0 A
8.0 A
A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are, respectively, M and R.G are gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth is
The density of material in CGS system of units is 4g/ cm^{2}.In a system of units in which unit of lengths is 10 cm and unit of mass is 100 g, the value of density of material will be
0.4
40
400
400
A particle covers half of its total distance with speed v_{1} and the rest half distance with speed v_{2}. Its average speed during the complete journey is
v_{1}v_{2 }/ v_{1} + v_{2}
2v_{1}v_{2}/v_{1} + v_{2}
2v_{1}^{2}v^{2}_{2} / v_{1}^{2} + v^{2}_{2}
2v_{1}^{2}v^{2}_{2} / v_{1}^{2} + v^{2}_{2}
A conveyor belt is moving at a constant speed of 2 m/s. A box is gently dropped on it. The coefficient of friction between them is μ = 0.5. The distance that the box - will move relative to belt before coming to rest on it taking
g= 10 ms^{-2 is}
1.2 m
0.6 m
zero
zero
A mass m moving horizontally (along the x -axis) with velocity v collides and sticks to mass of 3m moving vertically upward (along the y -axis) with velocity 2v. The final velocity of the combination
A small mass attached to a string rotats on frictionless table top as shown. If the tension is the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of 2, the kinetic energy of the mass will
remain constant
increase by a factor of 2
increase by a factor 4
increase by a factor 4
A particle of mass M is situated at the centre of spherical shell of mass and radius a. Th magnitude of the gravitational potential at a points situated at a/2 distance from the centre, will be
2GM/a
3GM/a
4GM/a
4GM/a
A projectile is fired an angle of 45^{o} with the horizontal.Elevation angle of the projectile at the highest point as seen from the point of projection is
60^{o}
tan^{-1}(1/2)