List of practice Questions

Two coherent monochromatic light beams of intensities 4I and 9I are superposed. The maximum and minimum possible intensities in the resulting beam are
An electron in a stationary Bohr orbit of hydrogen atom jumps from 4th energy level to the ground state. The velocity that the photon acquired as a result of electron transition will be (h = Planck's constant, R = Rydberg's constant, m = mass of photon)
A stretched string under tension fixed at both ends vibrates in the 4th harmonic. The equation of the stationary wave is \( Y = 3 \sin(200\pi t) \cos(0.4x) \), where \( x \) and \( y \) are in cm and \( t \) in seconds. The length of the vibrating string is
The resonance tube is filled with a liquid of density higher than that of water, then the resonating frequency
When Young's double slit experiment is performed in liquid, 8\(^\text{th}\) bright band is found to lie where 5\(^\text{th}\) dark band lies in air. Refractive index of liquid is
The upward force of 10\(^5\) dyne due to surface tension is balanced by the force due to the weight of the water column and \( h \) is the height of water in the capillary. The inner circumference of the capillary is (Surface tension of water = \( 7 \times 10^{-2} \) N/m)
The range of the voltmeter is \( V \) when \( 50 \, \Omega \) resistance is connected in series. Its range gets doubled when \( 500 \, \Omega \) resistance is connected in series. The resistance of the voltmeter is
In Boolean algebra the output \( C \) and the inputs \( A \) and \( B \) are related as \( C = \overline{A \cdot B} \). The logic gate corresponding to this equation is
A capacitor \( C_1 = 4 \, \mu F \) is connected in series with another capacitor \( C_2 = 1 \, \mu F \). The combination is connected across a d.c. source of 200 V. The ratio of potential across \( C_2 \) to that across \( C_1 \) is
In potentiometer experiment, for a given current, the balancing length for a cell is obtained at \( L \) cm. If the current through potentiometer wire is decreased, then the balancing length will
If \( f \) is the number of degrees of freedom of a molecule of a gas and ratio of molar specific heats of a gas, \( \gamma = 1 + \frac{2}{f} \) where \( \gamma = \frac{C_p}{C_v} \). The ratio of \( \gamma \) for monoatomic gas to \( \gamma \) for (rigid) diatomic gas is
In non-uniform circular motion, the ratio of tangential acceleration to radial acceleration is \( (r = \) radius of circle, \( V = \) speed and \( \alpha = \) angular acceleration)
When light of wavelength \( \lambda \) is incident on a photosensitive surface, the stopping potential is \( V \). When light of wavelength \( 3\lambda \) is incident on the same surface, the stopping potential is \( \frac{V}{6} \). Threshold wavelength for the surface is
Find the intensity of magnetization of a magnet with moment \( 4 \, \text{Am}^2 \) which weighs 50 grams. (Density of the material of a magnet = 5000 kg/m\(^3\))
In hydrogen atom, the product of the angular momentum and the linear momentum of the electron is proportional to \( (n = \) principal quantum number)
In a parallelogram shown below, \( a^2 + b^2 = ? \)
A wire of length \( L \), mass \( M \), density \( \rho \), radius \( R \) is stretched by a certain load. If \( r \) and \( \ell \) are the changes in radius and length respectively, then Poisson's ratio is
A transistor is used as a common emitter amplifier with a load resistance of 2 k\(\Omega\). The input resistance is 150 \(\Omega\). Base current is changed by 20 \(\mu A\), which results in a change in collector current by 1.5 mA. The amplified voltage gain of the amplifier is
Two unknown resistances are connected in two gaps of a meter bridge. The null point is obtained at 40 cm from the left end. A 30 \(\Omega\) resistance is connected in series with the smaller of the two resistances, the null point shifts by 20 cm to the right end. The value of the smaller resistance is
In photoelectric emission, the intensity of incident light is reduced then stopping potential
Two wires of the same length and material are used to form a square loop and a circular loop respectively. If the same current is passed through both loops, then the ratio of the magnetic moment of the square loop to that of the circular loop is
Out of the following graphs, which graph shows the correct relation for an LC parallel resonant circuit?
An ammeter is obtained by shunting an \( n \, \Omega \) galvanometer with \( n \, \Omega \) resistance. The additional shunt required to be connected across it to double the range is
A uniform rod of length \( 2L \) has constant mass per unit length \( m \). The moment of inertia of the rod about an axis passing through its center and perpendicular to its length is
Capacity of a parallel plate air condenser is 2 μF and voltage between the plates is changing at the rate of 3 V/s. The displacement current in the capacitor is