List of top Physics Questions

Two coplanar and concentric circular loops \( L_1 \) and \( L_2 \) are placed coaxially with their centres coinciding. The radii of \( L_1 \) and \( L_2 \) are 1 cm and 100 cm respectively. Calculate the mutual inductance of the loops. (Take \( \pi^2 = 10 \))
A rectangular coil of \(N\) turns and area of cross-section \(A\) is rotated at a steady angular speed \(\omega\) in a uniform magnetic field. Obtain an expression for the emf induced in the coil at any instant of time.
The magnetic flux through a coil of resistance 5 \(\Omega\) increases with time as: \(\Phi = (2.0 t^3 + 5.0 t^2 + 6.0 t)\) mWb. Find the magnitude of induced current through the coil at \(t = 2\) s.
A galvanometer of resistance \( G \) is converted into a voltmeter of range \( (0 - V) \) by using a resistance \( R \). Find the resistance, in terms of \( R \) and \( G \), required to convert it into a voltmeter of range \( (0 - \frac{V}{2}) \).
What is meant by current sensitivity of a galvanometer? Mention the factors on which it depends.
Show that the electric field for the same charge density \(\sigma\) is twice in case of a conducting plate or surface than in a nonconducting sheet.
A charge \( +Q \) is placed on a thin conducting spherical shell of radius \( r \). Derive an expression for the electric field at a point lying (i) inside and (ii) outside the shell.
A charge of \( 6 \, \mu C \) is given to a hollow metallic sphere of radius 0.2 m. Find the potential at (i) the surface and (ii) the centre of the sphere.
Obtain the expression for the capacitance of a parallel plate capacitor with a dielectric medium between its plates.
The number of bright fringes formed due to interference on 1 m of screen placed at \(\frac{4}{3}\) m away from the slits is:
Consider the diffraction of light by a single slit described in this case study. The first minimum falls at an angle equal to:
If instead of 450 nm light, another light of wavelength 680 nm is used, the number of peaks of the interference formed in the central peak of the envelope of the diffraction pattern will be:
The number of peaks of the interference formed if the slit width is doubled while keeping the distance between the slits same will be:
The number of peaks of the interference fringes formed within the central peak of the envelope of the diffraction pattern will be:
An electron is projected from the right plate of set I directly towards its left plate. It just comes to rest at the plate. The speed with which it was projected is about:
(Take \( \frac{e}{m} = 1.76 \times 10^{11} \, C/kg} \))
Let \(E_1\), \(E_2\), \(E_3\), and \(E_4\) be the magnitudes of the electric field between the pairs of plates, I, II, III, and IV respectively. Then:
The figure shows four pairs of parallel identical conducting plates, separated by the same distance of 2.0 cm and arranged perpendicular to the x-axis. The electric potential of each plate is mentioned
parallel identical conducting plates
(i) For which pair of the plates is the electric field E alongˆ i?
On the basis of energy band diagrams, distinguish between (i) an insulator, (ii) a semiconductor, and (iii) a conductor.
Draw the circuit diagrams for obtaining the V-I characteristics of a p-n junction diode. Explain briefly the salient features of the V-I characteristics in (i) forward biasing, and (ii) reverse biasing.
(a) Define atomic mass unit (u).
(b) Calculate the energy required to separate a deuteron into its constituent parts (a proton and a neutron).
\( m_D = 2.014102 \, u} \)
\( m_H = 1.007825 \, u} \)
\( m_n = 1.008665 \, u} \)
Use the Bohr's first and second postulates to derive an expression for the radius of the nth orbit in a hydrogen atom.
The electric field in an electromagnetic wave in vacuum is given by:
\(\vec{E} = 6.3 \, N/C} \left[\cos \left(1.5 \, rad/m} \cdot y + 4.5 \times 10^8 \, rad/s} \cdot t\right)\right] \hat{i}\) % Part (a) Wavelength and Frequency Calculation (a) Find the wavelength and frequency of the wave:
A sinusoidal voltage is applied to an electric circuit containing a circuit element `X' in which the current leads the voltage by \(\pi/2\).
(a) Identify the circuit element `X' in the circuit:
(b) Write the formula for its reactance:
(c) Show graphically the variation of this reactance with frequency of ac voltage:
To illustrate the relationship graphically:
Two long straight parallel conductors carrying currents exert a force on each other. Why? Derive an expression for the force per unit length between two long straight parallel conductors carrying currents in opposite directions. Explain the nature of the force between these conductors.
Determine the current in branches AB, AC, and BC of the network shown in the figure.
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