List of top Physics Questions

Calculate the Reynolds number for a liquid with density 1 g/cm³ and viscosity 8 × 10⁻⁴ Pa·s, flowing at 0.5 m/s through a pipe of diameter 4 cm.
How is the p-n junction diode used as the full wave rectifier ? Explain its working by drawing simple circuit.
The ratio of the efficiencies of two Carnot engines A and B is 1.25 and the temperature difference between the source and the sink is the same in both engines. The ratio of the absolute temperatures of the sources of the engines A and B is
A proton and an \( \alpha \)-particle are accelerated by the same potential difference. Find out the ratio of their de Broglie wavelengths.
The power rating of a ceiling fan rotating with a constant torque of 2 Nm with an angular speed of 2\(\pi\) rad/s will be ............
A planet revolves around the sun with a time period 27 times that of planet B. Planet A is at \( x \) times the distance of planet B from the sun. Find the value of \( x \).
Establish the formula of magnetic dipole moment.
Prove that total internal reflection of light ray from refracting surface is possible only when the value of angle of prism A be more than \(\sin^{-1}\left(\frac{1}{n}\right)\), where 'n' is refractive index of the material of prism.
If the breaking strength of a rope is $\frac{4}{3}$ times the weight of a person, then the maximum acceleration with which the person can safely climb up the rope is (g - acceleration due to gravity)
The resistance of 8 ohm and inductive reactance of 6 ohm are connected in series in an alternating current circuit. The impedance of circuit will be :
State the formula for magnetic induction produced by a current in a circular arc of a wire. Hence find the magnetic induction at the centre of a current carrying circular loop.

The figure shows an opamp circuit with a 5.1 V Zener diode in the feedback loop. The opamp runs from \( \pm 15 \, {V} \) supplies. If a \( +1 \, {V} \) signal is applied at the input, the output voltage (rounded off to one decimal place) is:


 

The elastic potential energy stored in a copper rod of length one meter and area of cross-section \(1 \, \text{mm}^2\) when stretched by 1 mm is:
In an electric circuit, three resistors \( 5 \, \Omega \), \( 10 \, \Omega \) and \( 15 \, \Omega \) are connected in series across a \( 60 \, V \) battery. Then the current flowing in the circuit is:
Which of the following materials belongs to diathermanous substance?
What is Ferromagnetism? Explain it on the basis of domain theory.

State Kirchhoff's law related to electrical circuits. In the given metre bridge, balance point is obtained at D. On connecting a resistance of 12 ohm parallel to S, balance point shifts to D'. Find the values of resistances R and S.

Distinguish between interference and diffraction of light. A double slit arrangement produces interference fringes for sodium light of wavelength 589 nm, that are 0.20 degree apart. What is the angular fringe separation if the entire arrangement is immersed in water? (R.I. of water = 1.33)
State Einstein's photoelectric equation and mention physical significance of each term involved in it. The wavelength of incident light is 4000Å. Calculate the energy of incident photon.
A galvanometer has a resistance of 50 \(\Omega\) and a current of 2 mA is needed for its full scale deflection. Calculate resistance required to convert it. (i) into an ammeter of 0.5 A range. (ii) into a voltmeter of 10 V range.
A solenoid of length \(\pi\) m and 5 cm in diameter has a winding of 1000 turns and carries a current of 5A. Calculate the magnetic field at its centre along the axis.
Diameter of a water drop is 0.6 mm. Calculate the pressure inside a liquid drop. (T = 72 dyne/cm, atmospheric pressure = \(1.013 \times 10^5\) N/m\(^2\))
Derive an expression for law of radioactive decay. Define one becquerel (Bq).
An electron in hydrogen atom stays in its second orbit for \(10^{-8}\) s. How many revolutions will it make around the nucleus in that time? [ Given : \(e = 1.6 \times 10^{-19}\) C, \(m = 9.1 \times 10^{-31}\) kg ]
Derive an expression for law of radioactive decay. Define one becquerel (Bq).