List of top Physics Questions

Write down the formula for refraction of light from a spherical surface and with the help of this, derive the relation \( \frac{1}{f} = (n - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right) \) for a thin lens. Also show that, the focal length for concave lens will be negative.
Mention the most important conclusion of Rutherford's alpha-particle scattering experiment. Define isotopic, isobaric, and isotonic nuclei. Find the energy equivalent to one atomic mass unit in joules and MeV (1 u = 1.6605 × \(10^{-27}\) kg).
What is the photoelectric effect? Which nature of light is shown by it? Threshold frequency of a metal is \(2.3 \times 10^{14}\) Hz. If the frequency of incident light is \(8.2 \times 10^{14}\) Hz, what will be the stopping potential? Calculate work function of the metal also.
What is meant by magnetic effect of electric current? Find the expression for the force acting between two parallel current-carrying conducting wires. On this basis, define the unit of electric current 'ampere'.
Derive the formula for the capacitance of a parallel plate capacitor partially filled with a dielectric medium between the plates.
State Huygens' principle of secondary wavelets. With the help of this principle, explain the laws of reflection of light.
With the help of given circuit, find out:
(i) Equivalent capacity of the combination
(ii) Charge on capacitor \(c_1\)
(iii) Total stored energy of the combination.}
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In A.C. circuits, what is the difference between impedance and resistance? Write the formula for power factor in L-C-R circuit.
What is an astronomical telescope? Draw ray diagram for an astronomical telescope when final image is formed at infinity.
State Gauss's law in electrostatics. On the basis of it, obtain the formula for the electric field produced due to a plane charged plate.
Explain the working method of p-n junction diode in reverse bias with the help of a circuit diagram.
Which nature of light is supported by Young's double slit experiment? The light used in Young's double slit experiment contains two wavelengths, 6000 \AA\ and 5000 \AA. Separation between the slits is \(10^{-3}\) m and the screen is at a distance of 1 m from the slits. Find minimum distance from the central maxima where bright fringes for both the wavelengths are coincident.
Write down the equation for Lorentz force. An electron passes undeviated from a place where an electric field \(5 \times 10^4~\text{V/m}\) and magnetic field of \(5 \times 10^{-2}~\text{weber/m}^2\) are applied. Calculate the velocity of the electron.
Give pictorial representation of polarized and unpolarised light. Polarizing angle for a transparent medium is 60°. Find the value of angle of refraction and refractive index of the medium.
Explain the meaning of binding energy of a nucleus. Write the dependency of binding energy per nucleon on the mass number of the nucleus.
What is the meaning of electrical capacity of a conductor? Find the unit of the electrical capacity of the conductor.
With the help of the given circuit, find out the total resistance of the circuit and the current flowing through the cell.
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Name the waves of longest wavelength and highest frequency in the given electromagnetic waves — microwaves, X-rays, radio waves, and \(\gamma\)-rays. What is meant by displacement current?
What is the meaning of stationary orbit of atom? Deriving formula for the energy of the electron in the stationary orbit of the hydrogen atom, mention its relation with the radius of the orbit of electron.
Equation of electric field of a plane electromagnetic wave is given as:
\[ E_z = 60 \sin(500x + 1.5 \times 10^{11} t) \, \text{V/m}. \] Write the equation for the magnetic field of the wave.
On which principle does a nuclear reactor work?
Write de-Broglie formula for the wavelength of matter waves.
On connecting a cell of e.m.f. 0.5 volt with an external resistance of 1.9 $\Omega$, the current flowing is 0.75 A. The internal resistance of the cell is:
In an alternating circuit, the reading of the voltmeter is 220 V. Write the peak value of the voltage.
Write down Einstein's equation for the photoelectric effect.