List of top Physics Questions

In a series LCR circuit an ac voltage source is connected. When inductor is removed from the circuit, the phase difference between the voltage and the current in the circuit is \(\frac{π}{3}\). If capacitor is removed from the circuit instead of inductor, the phase difference is again \(\frac{π}{3}\). What is the power factor of the circuit?

The mutual inductance M₁₂ of coil 1 with respect to coil 2:

Choose the correct statements from the following:
A. Induced emf opposes any change in the current in a circuit
B. Induced emf in a closed coil can be increased by increasing the number of turns in the coil
C. Varying current in a coil can not induce emf in a neighbouring coil.
D. An LCR circuit has zero impedance at resonant frequency
E. Average power supplied to an inductor over one complete cycle is zero
Choose the correct answer from the options given below:

Which of the following statements are correct?
A. Number of photoelectrons emitted per second is directly proportional to the intensity of incident radiation
B. Cut off potential is the minimum negative potential given to the plate for which photocurrent becomes maximum
C. For a given frequency of the incident radiation, the stopping potential is independent of its intensity
D. Even for the exceedingly dim incident radiation apparent time lag is~ 109s or less
E. Photons are electrically neutral and are not deflected by electric and magnetic fields
Choose the correct answer from the options given below:

Find moment of inertia about axis shown which is equidistant from both spheres

PARAGRAPH "II" A cylindrical furnace has height (𝐻) and diameter (𝐷) both 1 m. It is maintained at temperature 360 K. The air gets heated inside the furnace at constant pressure 𝑃𝑎 and its temperature becomes 𝑇 = 360 𝐾. The hot air with density 𝜌 rises up a vertical chimney of diameter 𝑑 = 0.1 m and height ℎ = 9 m above the furnace and exits the chimney (see the figure). As a result, atmospheric air of density 𝜌𝑎 = 1.2 kg m−3, pressure 𝑃𝑎 and temperature 𝑇𝑎 = 300 K enters the furnace. Assume air as an ideal gas, neglect the variations in 𝜌 and 𝑇 inside the chimney and the furnace. Also ignore the viscous effects. [Given: The acceleration due to gravity 𝑔 = 10 m s−2 and 𝜋 = 3.14] Considering the air flow to be streamline, the steady mass flow rate of air exiting the chimney is _______ gm s−1.

An annular disk of mass 𝑀, inner radius 𝑎 and outer radius 𝑏 is placed on a horizontal surface with coefficient of friction 𝜇, as shown in the figure. At some time, an impulse ℐ₀𝑥̂ is applied at a height ℎ above the center of the disk. If ℎ = ℎ𝑚 then the disk rolls without slipping along the 𝑥-axis.Which of the following statement(s) is(are) correct?