List of top Physics Questions

When LED is manufactured by using aluminium gallium arsenide (AlGaAs), it emits

A simple pendulum starts oscillating simple harmonically from its mean position (\(x = 0\)) with amplitude ' \(a\) ' and periodic time ' \(T\) '. The magnitude of velocity of pendulum at \(x = \frac{a}{2}\) is

A gas having (\gamma = \frac{5}{2}) and volume (360 c.c.) is suddenly compressed to (90 c.c.) If initial pressure is (P), then final pressure will be

In YDSE, the intensity where path difference is (\frac{\lambda}{4}) is (\frac{K}{4}). The intensity at a point when path difference is ' (\lambda) ' will be

A charge is uniformly distributed on the surface of a spherical rubber balloon. As it is blown up, the total electric flux coming out of the surface

Resolving power of a telescope can be increased by increasing

The ratio of the total energy of the (2^{nd}) orbit electron for the hydrogen atom ((^{1}H)) to that of a helium ion ((He^{+})) is :

A star radiates heat as a black body at temperature ' (T) '. The total radiant energy per unit area received at a distance ' (R) ' from the centre of a star of radius ' (r) ' is : ((\sigma =) Stefan's constant)

An organ pipe closed at one end has fundamental frequency of (1500 Hz). The maximum number of overtones generated by this pipe which a normal person can hear is (Normal man hears up to (19.5 kHz))

The magnetic field ((B)) inside a long solenoid carrying current ' (i) ' with an iron core is (( \mu_0 =) vacuum permeability, (\chi =) susceptibility)

A particle of mass \(200 \text{ g}\) is executing S.H.M. of amplitude \(0.2 \text{ m}\). At mean position, K.E. is \(16 \times 10^{-3} \text{ J}\). The equation of motion is:

Three rods of same mass are placed as shown in figure. The co-ordinates of centre of mass of the system are

Three immiscible transparent liquids with indices \(3/2\), \(4/3\) and \(6/5\) are arranged one above the other. The depths are \(3 \text{ cm}\), \(4 \text{ cm}\) and \(6 \text{ cm}\) respectively. The apparent depth of the vessel is.

A circular coil has radius ' \(R\) '. The distance from centre on axis where induction is \(1/27\) th of its value at centre is.

A liquid drop splits into \(729\) identical spherical drops. If \(E\) is the original energy and \(U\) is the total resulting energy , then \(E/U = 1/x\). The value of \(x\) is.

\(500 \text{ gram}\) of a diatomic gas is enclosed at a pressure of \(10^{5} \text{ Nm}^{-2}\). The density of the gas is \(5 \text{ kg m}^{-3}\). The energy of one mole of the gas due to its thermal motion is [consider the gas molecule as a rigid rotator].

All the springs in fig. (a), (b) and (c) are identical, each having force constant \(K\). Mass \(m\) is attached to each system. If \(T_{a}\), \(T_{b}\) and \(T_{c}\) are the time periods of oscillations in fig. (a), (b) and (c) respectively, then:

A physical quantity ' \(X\) ' is related to four quantities as \(X = a^2 b^3 c^{5/2} d^{-2}\). The percentage error in 'a', 'b', 'c' and 'd' are \(1%\), \(2%\), \(2%\) and \(4%\) respectively. The percentage error in ' \(X\) ' is.

In metre-bridge experiment the balance point is obtained if the gaps are closed by \(2 \Omega\) and \(3 \Omega\). A shunt of \(x \Omega\) is added to \(3 \Omega\) resistor to shift the balance point by \(22.5 \text{ cm}\). The value of \(x\) is.

Two vectors \(a\hat{i} + b\hat{j} + \hat{k}\) and \(2\hat{i} - 3\hat{j} + 4\hat{k}\) are perpendicular. When \(3a + 2b = 7\) , the ratio \(a/b\) is \(x/2\). The value of \(x\) is.

A coil of area \(3 \text{ m}^{2}\) is at right angles to a magnetic field of \(0.05 \text{ Wb/m}^{2}\). If the field is decreased to \(20%\) of its value in \(10 \text{ s}\) , the induced e.m.f. is.

The relation between efficiency ((\eta)) of Carnot engine and coefficient of performance ((\beta)) of refrigerator is

A radioactive element having half-life (30 min) is undergoing beta decay. The fraction of radioactive element remains undecayed after (90 min) will be

The potential difference across the (4 \muF) capacitor in the following circuit is

The moment of inertia of a thin uniform rod of mass ' (M) ' and length ' (L) ', about an axis perpendicular to length and at a distance ' (L/4) ' from one end is