List of top Physics Questions

When 100 V dc is applied across a solenoid, a current of 1 A flows in it. When 100 V ac is applied across the same solenoid the current drops to 0.5 A. If the frequency of the ac source is 50 Hz, the impedance and inductance of the solenoid are:

In an a.c. circuit, the rms voltage is \(100\sqrt{2}\) V. The peak value of voltage would be:

Find the effective impedance in the circuit if the source is: a) DC source and b) High frequency AC source

Which one out of the following is not an application of eddy currents?

A square loop of copper wire is pulled through a region of uniform magnetic field as shown. Rank the pulling forces \(F_A\), \(F_B\), \(F_C\), and \(F_D\) that must be applied to keep the loop moving with constant speed (\(\vec{v}\)):

To protect galvanometer from possible damages due to large current, which of the following should be connected to its coil:

The charge which is a source of electric field but not of magnetic field is:

A uniform magnetic field, parallel to the plane of the paper existed in space initially directed from left to right. When a bar of soft iron is placed in the field parallel to it, the lines of force passing through it will be represented by:

Magnetic field \(|B|\) at a point \(P\) in the following network is:

There is a thin conducting wire carrying current. The value of magnetic field induction at any point on the conductor would be:

The coercivity of a bar magnet is 140 A m\(^{-1}\). To demagnetize it, it is placed inside a solenoid of length 1.6 m and number of turns 112. What is the current flowing through the solenoid?

A cell of constant emf is first connected to a resistance \(R_1\) and then to \(R_2\). If power delivered in both cases are same, then the internal resistance of the cell is:

Identify the graph from the following showing the temperature dependence of resistivity for a typical semiconductor?

Kirchhoff's Second Law is based on law of conservation of:

Three capacitors of capacitances 3 \(\mu\)F, 6 \(\mu\)F and 12 \(\mu\)F are connected in series. Find the potential difference across the 6 \(\mu\)F capacitor, if a battery of 7 V is connected across this combination:

A room heater is rated 750 W, 220 V. An electric bulb rated 200 W, 220 V is connected in series with this heater. What will be the power consumed by the bulb and the heater respectively, when the supply is at 220 V?

The electric field intensity due to an infinite thin plane sheet of surface charge density \(\sigma\) is:

In a potentiometer arrangement, a cell of 1.5 V gives a balance point at 45.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 75.0 cm, what is the emf of the second cell?

Choose the correct statements from the following:
A. The total charge in any isolated system remains constant.
B. When some charge is transferred to a conductor, it stays at the same place without getting distributed over the entire surface.
C. One Coulomb of negative charge is the total charge of \(6.25 \times 10^{18}\) electrons.
D. Electric field is a scalar field.
E. Permanent dipole means that the dipole moment \(\vec{P}\) exists irrespective of external electric field \(\vec{E}\).

An isolated sphere has a capacitance of 60 pF, what is the radius of the sphere?

Choose the correct answer from the following:
If three charged particles are collinear and are in equilibrium, then:

Choose the correct alternative from the following:

As shown in the figure, a liquid is at the same levels in two arms of a U-tube of uniform cross-section when at rest. If the U-tube moves with an acceleration 'f' towards the right,the difference in liquid heights between the two arms of the U-tube will be,(acceleration due to gravity=g)

In a Young's double slit experiment which of the following statements is NOT true?