List of practice Questions

A convex lens of focal length $ f = 20 \, \text{cm} $ is combined with a diverging lens of power 65 D. The power and the focal length of the combination is
According to the thin lens formula, which one of the following is true regarding the focal length of the lens?
What happens to the kinetic energy of the emitted electrons when the light is incident on a metal surface?
Which of the following is a necessary condition for total internal reflection?
Multimode graded index fibers are manufactured from materials with ______.
A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then what is its focal length?
Which of the following can be used to produce a propagating electromagnetic wave?
Which type of transmission line accepts the Transverse electromagnetic wave?
Which of the following cannot travel in vacuum?
How is a galvanometer converted into an ammeter?
Find the force due to a current element of length 2 cm and flux density of 12 tesla. The current through the element will be 5A.
Which of the following statement is valid?
_______ the resonant frequency, the current in the capacitor leads the voltage in a series RLC circuit.
A steady current flows in a metallic conductor of non-uniform cross-section. Which of the following quantities is constant along the conductor?
Resistor Color codes were developed by:
36 cells, each of emf 4V are connected in series and kept in a box. The combination shows an emf of 88V on the outside. Calculate the number of cells reversed.
If a coil carrying current is placed in a uniform magnetic field, then
If the current $ I $ flows through the coil of radius $ r $, then the field at the center of the circular coil is
What is meant by mean free path?
The property which differentiates two kinds of charges is called
What happens when a glass rod is rubbed with silk?
Two charges $Q_1$ and $-Q_2$ are separated by a distance $r$. The charges attract each other with a force $F$. What is the new force between the charges if the distance is cut to one-fourth and the magnitude of each charge is doubled?
X is a substance which does not allow the flow of charges through it but permits them to exert electrostatic forces on one another through it. Identify X.
The opposition offered by the electrolyte of the cell to the flow of current through itself is known as .
Which of the following is not a gas law?