The escape velocity from the Earth’s surface is v. The escape velocity from the surface of another planet having radius four times that of Earth and the same mass density is:
(1) v (2) 2v
(3) 3v (4) 4v Continue reading The escape velocity from the Earth’s surface is v ….
The half-life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be:
(1) $\frac {1}{2}$ (2) $\frac {1}{2\sqrt 2}$
(3) $\frac {2}{3}$ (4) $\frac {2}{3\sqrt 2}$ Continue reading The half-life of a radioactive nuclide is 100 hours ….
For a plane electromagnetic wave propagating in x-direction, which one of the following combination gives the correct possible directions for electric field (E) and magnetic field (B) respectively?
(1) $\hat j + \hat k, \hat j + \hat k $
(2) $-\hat j + \hat k, -\hat j – \hat k $
(3) $\hat j + \hat k, -\hat j – \hat k $
(4) $-\hat j + \hat k,-\hat j+\hat k $ Continue reading For a plane electromagnetic wave propagating in x-direction ….
A small block slides down on a smooth inclined plane, starting from rest at time t = 0. Let $S_n$ be the distance travelled by the block in the interval t = n-1 to t = n. Then, the ratio $\frac {S_n}{S_{n+1}}$ is:
(1) $\frac {2n-1}{2n}$
(2) $\frac {2n-1}{2n+1}$
(3) $\frac {2n+1}{2n-1}$
(4) $\frac {2n}{2n-1}$ Continue reading A small block slides down on a smooth inclined plane ….
A particle is released from height H above the ground. At a certain instant its kinetic energy is three times its potential energy. The height h above the ground and the speed of the particle v at that instant are respectively:
(1) $\frac {H}{4},\frac {3gH}{2}$
(2) $\frac {H}{4},\frac {\sqrt {3gH}}{2}$
(3) $\frac {H}{2},\frac {\sqrt {3gH}}{2}$
(4) $\frac {H}{4},\sqrt {\frac {3gH}{2}}$ Continue reading A particle is released from height H above the ground ….
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? ($g=10 m/s^2$)
(1) 10.2 kW
(2) 8.1 kW
(3) 12.3 kW
(4) 7.0 kW Continue reading Water falls from a height of 60 m at the rate of 15 kg/s ….
In a potentiometer circuit, a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?
(1) 60 cm
(2) 21.6 cm
(3) 64 cm
(4) 62 cm Continue reading In a potentiometer circuit, a cell of EMF 1.5 V ….
