HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Important Questions for Physics

A parallel plate air condenser has a capacity of 20µF. What will be a new capacity if:

1) the distance between the two plates is doubled?

2) a marble slab of dielectric constant 8 is introduced between the two plates?

Answer the following:

State the principles of the electric motor and electric generator. 

Choose the correct option:

A conductor rod of length (l) is moving with velocity (v) in a direction normal to a uniform magnetic field (B). What will be the magnitude of induced emf produced between the ends of the moving conductor?

What is the energy required to build up current of 1A in an inductor of 20 mH?

In a Faraday disc dynamo, a metal disc of radius R rotates with an angular velocity ω about an axis perpendicular to the plane of the disc and passing through its center. The disc is placed in a magnetic field B acting perpendicular to the plane of the disc. Determine the induced emf between the rim and the axis of the disc.

A horizontal wire 20 m long extending from east to west is falling with a velocity of 10 m/s normal to the Earth’s magnetic field of 0.5 × 10⁻⁴ T. What is the value of induced emf in the wire?

A search coil having 2000 turns with area 1.5 cm² is placed in a magnetic field of 0.60 T. The coil is moved rapidly out of the field in a time of 0.2 s. Calculate the induced emf in the search coil.

An aircraft of wing span of 50 m flies horizontally in the Earth's magnetic field of 6 x 10^-5 T at a speed of 400 m/s. Calculate the emf generated between the tips of the wings of the aircraft.

A circular coil of 100 turns with a cross-sectional area of 1 m² is kept with its plane perpendicular to the magnetic field of 1 T. The magnetic flux linkage is ______.

In which of the following devices, the eddy current is not used ______ 

The role of inductance is equivalent to ______ 

In the expression e = –dΦ/dt, the -ve sign signifies ______ 

Distinguish between Step up and Step Down Transformer.

What is Transformer?

A plane of a coil of 10 turns is tightly wound around a solenoid of diameter 2 cm having 400 turns per centimeter. The relative permeability of the core is 800. Calculate the inductance of the solenoid. 

Obtain an expression for the self-inductance of a solenoid.

Find an expression for the power expended in pulling a conducting loop out of a magnetic field.

Two inductor coils with inductance 10 mH and 20 mH are connected in series. What is the resultant inductance of the combination of the two coils?

An emf of 91 mV is induced in the windings of a coil when the current in o nearby coil is increasing at the rate of 1.3 A/s. what is the mutual inductance (M) of the two coils in mH?

Derive an expression for energy stored in the magnetic field in terms of induced current.