List of top Physics Questions

The linear displacement \( x \) of the bob of simple pendulum from its mean position varies as \( x = a \sin \left( \frac{\pi}{2} t \right) \), where \( a \) is its amplitude expressed in meter and \( t \) is in second. The length of simple pendulum is (Take \( g = \pi^2 \, \text{m/s}^2 \))

The period of seconds pendulum on a planet, whose mass and radius are three times that of earth, is

A simple pendulum of length \( L \) has mass \( M \) and it oscillates freely with amplitude \( A \). At extreme position its potential energy is \( (g = \text{acceleration due to gravity}) \)

In communication with the help of antenna, the range covered (for the line of sight propagation) is initially \(d\). If the height of antenna is doubled, the range covered would become

Seven capacitors each of capacitance $2\,\mu F$ are to be connected to obtain equivalent capacitance of $\dfrac{10{11}\,\mu F$. Which of the following combination is possible?}

In phase modulation, according to the information signal, a parameter of the carrier wave which is varied, is

Two parallel long wires 'A' and 'B' carry currents \( i_1 \) and \( i_2 \) (\( i_1<i_2 \)). When \( i_1 \) and \( i_2 \) are in the same direction, the magnetic field at a point midway between the wires is 10 µT. If \( i_2 \) is reversed, then the field becomes 30 µT. The ratio of \( \frac{i_1}{i_2} \) is

In an LCR circuit the inductance is changed from \( L \) to \( 9L \). For the same resonant frequency, the capacitance should be changed from \( C \) to

A block of mass \( M \) is pushed momentarily on a horizontal surface with initial velocity \( V \). If \( \mu \) is the coefficient of sliding friction between the block and surface, the block will come to rest after time \( t \) (where \( g \) is the acceleration due to gravity)

The electron in hydrogen atom is moving in an orbit of radius 0.53 Å. It takes \( 1.571 \times 10^{-16} \, \text{s} \) to complete one revolution. The velocity of electron will be

A coin is placed on a horizontal plate. The plate performs S.H.M. vertically with angular frequency \(\omega\). The amplitude \(A\) of oscillations is gradually increased. The coin will lose contact with the plate for the first time when amplitude is ( \(g\) = acceleration due to gravity )

In conversion of moving coil galvanometer into an ammeter of required range, the resistance of ammeter so formed is

If the ratio of amplitudes of two sound waves is \(4:3\), then the ratio of maximum and minimum intensities is

The angle made by a vector \( \vec{B} = 3\hat{i} + 2\hat{j} + 4\hat{k} \) with the y-axis is

If the kinetic energy of a particle is increased to 16 times its previous value, the percentage change in the de-Broglie wavelength of the particle is

Two identical parallel plate air capacitors are connected in series to a battery of e.m.f. \( V \). If one of the capacitors is inserted in liquid of dielectric constant \( K \), then potential difference of the other capacitor will become

One thousand small water drops of equal radii combine to form a big drop. The ratio of final surface energy to the total initial surface energy is

How much energy is imparted to an electron so that its de-Broglie wavelength reduces from \( 10^{-10} \) m to \( 0.5 \times 10^{-10} \) m?

A particle executes linear S.H.M. with amplitude 4 cm. The magnitudes of velocity and acceleration are equal when it is 3 cm from the mean position. The time period of motion is

A metal rod of Young’s modulus $Y$ and coefficient of linear expansion $\alpha$ has its temperature raised by $\Delta \theta$. The linear stress to prevent the expansion of rod is ($L$ and $\ell$ are original length of rod and expansion respectively)

A block of mass \( m \) attached to one end of the vertical spring produces extension \( x \). If the block is pulled and released, the periodic time of oscillation is

In a semiconductor, the number of holes and number of free electrons are represented as \( n_h \) and \( n_e \), respectively. Which one of the following statements is TRUE for the semiconductor?

The increase in length of a wire on stretching is \(0.05%\). If its Poisson’s ratio is 0.4, then its diameter is reduced by

A bullet of mass $20\,\text{g}$ moving with a velocity of $200\,\text{m/s}$ strikes a target and is brought to rest in $\left(\dfrac{1}{50}\right)^{\text{th}}$ of a second. The impulse and average force of impact are respectively

Two masses \( M_1 \) and \( M_2 \) are accelerated uniformly on a frictionless surface as shown in figure. The ratio of the tensions \( \left( \frac{T_1}{T_2} \right) \) is