List of top Physics Questions

A thin uniform rod of length \(2\) m cross-sectional area 'A' and density 'd' is rotated about an axis passing through the centre and perpendicular to its length with angular velocity \(ω\). If the value of \(ω\) in terms of its rotational kinetic energy \(E\) is \((αE/Ad)^{1/2}\), then the value of \(α\) is
Moment of inertia of a disc of mass \(M\) and radius 'R' about any of its diameter is \(MR^2/4\). The moment of inertia of this disc about an axis normal to the disc and passing through a point on its edge will be, \((x/2)MR^2\). The value of \(x\) is
If earth has a mass nine times and radius twice to the planet P. Then \(\frac{v_e}{3}\sqrt{x}\) ms\(^{-1}\) will be the minimum velocity required by a rocket to pull out of gravitational force of P, where \(v_e\) is escape velocity on earth. The value of \(x\) is
A solid sphere of mass \(1\) kg rolls without slipping on a plane surface. Its kinetic energy is \(7\times 10^{-3}\) J. The speed of the center of mass of the sphere in cm s\(^{-1}\) is
Spherical insulating ball and a spherical metallic ball of same size and mass are dropped from the same height. Choose the correct statement out of the following {Assume negligible air friction}
Calculate the values of \(a\) and \(b\) if vectors \(a\hat{i}+b\hat{j} = \hat{n}\) and \((\hat{i}+\hat{j})\) are perpendicular to each other
The length of a cylinder is measured with a meter rod having least count \(0.1\) cm. Its diameter is measured with vernier calipers having least count \(0.01\) cm. Length of cylinder is \(8.0\) cm and radius is \(4.0\) cm. Find the percentage error in the calculated value of the volume.
In transistor amplifier, base emitter junction is forward biased and collector base junction is reversed biased. The current gain is
Energy of the incident photons on the photosensitive metal surface is 3W and then 5W where 'W' is the work function of that metal. The ratio of velocities of the emitted photoelectrons is
An electron is revolving in a circular orbit of radius 'r' in hydrogen atom. Using Bohr's theory, the angular momentum of the electron is
(M = magnetic dipole moment, m = mass of electron)
The ratio of centripetal acceleration for an electron revolving in 3rd and 5th Bohr orbit of hydrogen atom is
In common emitter mode of transistor, the d.c. current gain is 20, the emitter current is 7 mA. The collector current is
In Young's double slit experiment, the angular width of a fringe is found to be \(0.2^{\circ}\) on a screen placed 1m away. The wavelength of light used in 600 nm. If the entire apparatus is immersed in water of refractive index 4/3. the angular width of the fringe will be
A resistor of 100 \(\Omega\), inductor of self inductance \((\frac{4}{π^2})\) H and a capacitor of unknown capacity are connected in series to an a.c. source of 200 V and 50 Hz. When the current and voltage are in phase, the value of capacity is
Choose the correct statement from the following.
Brewster's angle for a transparent medium is
If a parallel beam of light is incident on spherical mirrors then after reflection they pass through focal point. If F is the focal length and R is the radius of curvature of mirror then
An alternating e.m.f. is given by \(e = e_0sinωt\). In what time the e.m.f. will have half its maximum value, if 'e' starts from zero? (\(sin30^{\circ} = 0.5\))
According to corpuscular theory of light, Which is NOT the property of light?
If the number of turns in the coil of a moving coil galvanometer decreases, the resistance of the galvanometer,
In series LCR circuit C = 2 uF, L=1 mH and R= 10 \(\Omega\). What is the ratio of energies stored in the capacitor and inductor when maximum current flows through circuit?
Two coils P and Q have mutual inductance 'M' H. If the current in the coil P is \(I = I_0sinωt\), then the maximum value of e.m.f. induced in coil Q is
The magnetic flux near the axis and inside the air core solenoid of length 60 cm carrying current I is \(\frac{π}{2}\times 10^{-6}\) Wb. Its magnetic moment will be (cross-sectional area is very small as compared to length of solenoid, \(μ_0\) = Permeability of free space = \(4π\times 10^{-7}\) SI unit)
In series LCR resonant circuit, R=800 \(\Omega\), C = 2 \(μ\)F and voltage across resistance is 200 V. The angular frequency is 250 rad/s. At resonance the voltage across the capacitance is
Two wires A and B of equal lengths are connected in left and right gap respectively of a metre bridge, null point is obtained at 40 cm from left end. Diameters of the wires A and B are in the ratio 3:1 respectively, the ratio of specific resistance of A to that of B is
A potentiometer wire is 4 m long and potential difference of 3V is maintained between the ends. The e.m.f. of the cell which balances against a length of 100 cm of the poteniometer wire is