List of top Physics Questions

Circular disc of mass 2 kg and radius 1 m is rotating about an axis perpendicular to its plane and passing through its centre of mass with a rotational kinetic energy of 8 J. The angular momentum in (J-s) is
An intrinsic semiconductor at $0\,K$ temperature behaves like
The moment of inertia of a circular ring of mass $1\,kg $ about an axis passing through its centre and perpendicular to its plane is $4\, kg-m^{2}$ . The diameter of the ring is
If $g$ is the acceleration due to gravity on the surface of earth, its value at a height equal to double the radius of earth is
Hydrogen atom does not emit $X-rays$ because
Energy of a charged capacitor is $E$. It is allowed to share its charge with an identical capacitor charged to half its potential. Loss in the energy of the system is
Formation of Eddy currents has desirable effects in 1. Electromagnetic damping, 2. Transformer 3. Inductothermy
A person inside water $n_w = \frac{4}{3} $ sees the 'setting sun' at about
Two point charges are $3\, m$ apart and their combined charge is $8 \mu C$. The force of repulsion between them is $0.012\, N$. Charges are
In an interference experiment two parallel vertical slits $S_1$ and $S_2$ are used. A thin glass plate is introduced in the path of light from $S_1$. Then
A slab consists of two plates of different materials of same thickness and having thermal conductivities $K_1$ and $K_2$. The equivalent thermal conductivity of the slab is
Woollen clothes keep the body warm because they
The range of a particle projected at an angle of 15? with the horizontal is 1.5 km. Its range when projected with the same velocity at an angle of 45? with the horizontal is
A body when released from the top of a tower of height $h$ reaches the ground in time 1 second. Time in second at which it is a height $ \frac{h}{2}$ above the groun.d is
A charge situated at a certain distance along the axis of an electric dipole experience a force $F$. If the distance of the charge from the dipole is doubled, the force acting on it will become
A DC source of $30 \, V$ is connected across two resistors of $200\, \Omega$ each connected in series. A voltmeter of resistance $200 \, \Omega$ is connected across a resistor. It reads
The object at rest suddenly explodes into three parts with the mass ratio 2:1:1. The parts of equal masses move at right angles to each other with equal speeds. The speed of the third part after the explosion will be
'Raman frequencies' refers to
The angle between particle velocity and wave velocity in a transverse wave is
A long spring is stretched by $ 2\,cm $ and its potential energy is $ U $ . If the spring is stretched by $ 10\,cm $ ; its potential energy will be
A particle having almost zero mass and exactly zero charge is
A $ 20\,mu F $ capacitor is connected to $ 45\,V $ battery through a circuit whose resistance is $ 2000\, \Omega $ . What is the final charge on the capacitor ?
A change of $8.0 mA$ in the emitter current brings a change of $7.9 mA$ in the collector current. The values of $\alpha$ and $\beta$ are
A two litre glass flask contains some mercury. It is found that at all temperatures the volume of the air inside the flask remains the same. The volume of the mercury inside the flask is ( $ \alpha $ for glass $ =9\times {{10}^{-6}}/C,\gamma $ for mercury $ =\text{ }1.8\times {{10}^{-4}}/{}^\circ C $ )
A man is walking due east at the rate of 2 km/h. The rain appears to him to come down vertically at the rate of 2 km/h. The actual velocity and direction of rainfall with the vertical respectively are