List of practice Questions

State Faraday's law of electromagnetic induction. Briefly describe two methods for producing induced emf.
A deuterium nucleus and an alpha particle approach a target nucleus separately in head-on position. Find the ratio of their distance of closest approach to the nucleus, when both have the same velocity.
A deuterium nucleus and an alpha particle approach a target nucleus separately in head-on position. Find the ratio of their distance of closest approach to the nucleus, when both have the same momentum.
Show that $\frac{1}{\sqrt{\varepsilon_0 \mu_0}}$ gives the velocity of an electromagnetic wave in free space.
A ray of light is incident at angle of $45^\circ$ on one face of a prism with an equilateral triangular base. If it passes symmetrically through the prism, find the angle of minimum deviation for the prism
A ray of light is incident at angle of $45^\circ$ on one face of a prism with an equilateral triangular base. If it passes symmetrically through the prism, find the refractive index of the material of the prism.
With the help of circuit diagrams, briefly explain the forward biasing and the reverse biasing of a p-n junction diode.
Establish the relation between drift velocity of electrons ($v_d$) and electric current ($I$) in a conductor.
How is $v_d$ affected when the length of the conductor is doubled, keeping the voltage applied across the conductor constant ?
A circular coil of 30 turns and radius 8.0 cm carrying a current of 6 A is suspended vertically in a uniform horizontal magnetic field of 1.0 T. The field lines make an angle of $30^\circ$ with the plane of the coil. Calculate the magnitude of the external torque that must be applied to prevent the coil from turning. What would happen if the circular coil is replaced by a planar coil of irregular shape that encloses the same area, keeping other parameters unchanged ?
Light of frequency $5.0 \times 10^{14}$ Hz is incident on a metal surface. If the maximum speed of photoelectrons emitted is $6.63 \times 10^5$ ms$^{-1}$, calculate the threshold frequency for the surface.
In the given figure, a steady current I flows through the circuit when points A and C are connected by a wire of negligible resistance. Find the potential difference between points B and C.

A battery of emf 21 V and internal resistance 3 $\Omega$ is connected to a resistor. If the current in the circuit is 3 A, find the resistance of the resistor.
A battery of emf 21 V and internal resistance 3 $\Omega$ is connected to a resistor. If the current in the circuit is 3 A, find the terminal voltage of the battery.
In Young's double slit experiment, the central maximum is bright in the interference pattern obtained on a screen. What will happen when light waves emitted out of slits $S_1$ and $S_2$ have an initial phase difference of $\pi$ radian ? Justify your answers.
In Young's double slit experiment, the central maximum is bright in the interference pattern obtained on a screen. What will happen when one of the slits is closed ? Justify your answers.
Depict the variation of electric field ($\vec{E}$) and magnetic field ($\vec{B}$) with respect to the direction of propagation of an electromagnetic wave. Write their two important characteristics.
Assertion (A) : Photoelectric current depends upon the intensity of the incident radiation.
Reason (R) : Stopping potential is independent of the intensity of the incident radiation.
Assertion (A) : In a Wheatstone bridge circuit, if we interchange the position of the cell and the galvanometer, the balance condition \( \frac{P}{Q} = \frac{R}{S} \) remains unchanged.
Reason (R) : \( \frac{P}{Q} = \frac{R}{S} \Rightarrow \frac{Q}{S} = \frac{P}{R} \) so balance condition remains same.
Assertion (A) : The cylindrical soft iron core in a moving coil galvanometer only makes the magnetic field radial and does not affect the strength of the magnetic field.
Reason (R) : In a moving coil galvanometer, the plane of the coil is always perpendicular to the magnetic field.
Write any two points of difference between intrinsic and extrinsic semiconductors.
Explain the terms mass defect and binding energy. How are they related ?
If \( r_1 \) and \( r_2 \) are the radii of atomic nuclei of mass numbers 64 and 27 respectively, then the value of \( \left( \frac{r_1}{r_2} \right) \) is :
A ray of yellow light undergoes total internal reflection when it is incident at the interface of two media. This ray is successively replaced by the ray of blue, green and red lights. Which of the following statements is true if the angle of incidence is same in all cases ?
The ratio of the de Broglie wavelengths associated with the electron revolving in the first and third orbits in hydrogen atom is :