What force is required to give a projectile weighing 450. N an acceleration of 500. m/s²?
 1) 5.6 E 4 N
 2) 2.3 E 4 N
 3) 1.6 E 4 N
 4) 8.7 E 4 N

The distance to which an electron of a hydrogen atom is to be removed from the atom so that the force of electrostatic attraction is equal to six times the weight of the atom, will be :

[Take g=10 m/s² and number of atoms in 1 kg1 kg of monoatomic hydrogen is 66 x 10²⁶]

1) 1.2 cm

2) 4.8 cm

3) 2.4 cm

4) 3.6 cm

Equations of a stationary and a travelling waves are as follows, $${ y }_{ 1 }=a\sin { kx } \cos { \omega t } $$ and $${ y }_{ 2 }=a\sin { \left( \omega t-kx \right)  }$$. The phase difference between two points $${ x }_{ 1 }=\dfrac { \pi  }{ 3k } $$ and $${ x }_{ 2 }=\dfrac { 3\pi  }{ 2k } $$ are $${ \phi  }_{ 1 }$$ and $${ \phi  }_{ 2 }$$ respectively for two waves. The ratio $$\dfrac { { \phi  }_{ 1 } }{ { \phi  }_{ 2 } } $$ is :

1) 1
2) $${ 5 }/{ 6 }$$
3) $${ 3 }/{ 4 }$$
4) $${ 6 }/{ 7 }$$

A copper wire of length ll is bent into a semicircle. It is moved with a velocity vv in a region where magnetic field is uniform and perpendicular to the plane of the wire. If the strength of the field is B then emf induced is

1) Blv
2) $$B\displaystyle \dfrac{l}{\pi}v$$
3) $$B\displaystyle \dfrac{2l}{\pi}v$$
4) none of these

A block of wood is pulled along a horizontal bench at a constant speed of 15 m/s by a force of 8N. How much work is done against friction in 6 seconds?
 
 (1) 720J
 (2) 120J
 (3) 48J
 (4) 20J

A transmitter transmits at a wavelength of 300m A condenser of capacitance 2.4μF is being used. The value of the inductance for the resonant circuit is approximately

1) 10⁻⁴ H
2) 10⁻⁶ H
3) 10⁻⁸ H
4) 10⁻¹⁰ H

A diode can be used for:

(1) Rectification
(2) Detection
(3) Modulation
(4) Amplification

A glass of refractive index 1.5 is coated with a thin layer of thickness of tt of refractive index 1.8 light of wavelength λ tavelling at the upper and the lower surfaes of the layer and the two reflected rays interfere. If λ=648nm , obtain the least value of tt (in 10⁻⁸m) for which the rays interfere constructively.

1) 1.8 ×10⁻⁸m

2) 0.9 ×10⁻⁸m

3) 9×10⁻⁸m

4) 18×10⁻⁸m

The potential difference VV and the current II flowing through an instrument in an AC circuit are given by V=5cosωt volt,I=2sinωtAmp . The power dissipated in the circuit is

1) 5 watt
2) 10 watt
3) 2.5 watt
4) 0

Two marbles, one twice as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the ground, the heavier marble has:

1. Twice as much kinetic energy as the lighter one.

2. The same kinetic energy as the lighter one.

3. Four times as much kinetic energy as the lighter one.

4. Half as much kinetic energy as the lighter one.