List of top Physics Questions

Who said, “Number of transistors per square inch on integrated circuits double every year…”?

A concave lens is kept in contact with a convex lens of focal length \(20\,cm\). The combination works as a convex lens of focal length \(50\,cm\). The power of concave lens is:

The critical angle for glass-water interface (if \( \mu_g = \frac{3}{2}, \mu_w = \frac{4}{3} \)) is:

A man who wears glasses of power \(3D\) must hold a newspaper at least \(25\,cm\) away to see clearly. How far away would the newspaper have to be if he took off the glasses and still wanted clear vision?

The force per unit length between two parallel current carrying straight conductors separated by \(2d\) is given by the formula:

What is the current through the circuit and the potential difference across the diode shown in the figure. The drift current for the diode is \(30\,\mu A\).

When a dielectric slab is introduced between the plates of a capacitor connected to a battery, then:

On a heater coil it is written \(250\,V, 500\,W\). What is the resistance of this coil?

How much deep inside the earth (radius \(R\)) should a man go, so that his weight becomes one-fourth of that on the earth’s surface?

A wire of resistance \(5\,\Omega\) is drawn out so that its length is increased to twice its original length, its new resistance is:

The magnifying power of a telescope is \(m\). If the focal length of the eye piece is doubled, then its magnifying power becomes:

Four projectiles are thrown with the same initial speed at angles \(27^\circ, 36^\circ, 43^\circ, 51^\circ\) with the horizontal. The range of projectiles will be the largest for the projectile fired at angle:

The time period of a freely suspended magnet is \(4\,s\). If it is broken in length into two equal parts and one part is suspended in the same way, then the time period will be:

Half-life period of a radioactive substance is \(10\,\text{min}\). Then amount of substance decayed in \(40\,\text{min}\) will be:

A solid sphere of mass \(2\,kg\) rolls on a horizontal surface at \(10\,m/s\) and then rolls up a \(30^\circ\) incline. The maximum height reached is:

If one mole of monoatomic gas (\(\gamma = \frac{5}{3}\)) is mixed with one mole diatomic gas (\(\gamma = \frac{7}{5}\)), the value of \(\gamma\) for the mixture is:

Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and volume \(V\). The masses are \(m_A\) and \(m_B\). On isothermal expansion to \(2V\), pressure changes are \(\Delta p\) and \(1.5\Delta p\) respectively. The relation between masses is:

A spring of force constant \(k\) is cut into two pieces such that one piece is double the length of other. Then, the long piece will have a force constant of:

Five equal capacitors each with capacitance \(C\) are connected as shown in the figure. Then, the equivalent capacitance between \(A\) and \(B\) is:

An object is moving in a circle at constant speed \(v\). The magnitude of the rate of change of momentum of the object is:

A convex lens of focal length \(0.12\,m\) produces an image which is three times the size of the object. The distance between the object and the lens for a real image is:

Two coils have mutual inductance of \(1.5\,H\). If current in primary coil is suddenly raised to \(5\,A\) in one millisecond, the induced emf in the secondary coil is:

The formula for magnetic field of a certain component is given by \[ B = \frac{\mu_0 Ni}{2\pi r} \] where, \(N\) = total number of turns, \(i\) = current, \(r\) = radius. The component is:

If an observer moves towards a stationary source, then the apparent frequency is given by:

The horizontal component of earth’s magnetic field at a place is \(0.4 \times 10^{-4}\,T\). If the angle of dip is \(45^\circ\), the value of total intensity is: