HSC Science (Electronics) १२ वीं कक्षा - Maharashtra State Board Important Questions

The magnetic flux through a loop is varying according to a relation `phi = 6t^2 + 7t + 1` where `phi` is in milliweber and t is in second. What is the e.m.f. induced in the loop at t = 2 second?

Explain self induction and mutual induction

A cube of marble having each side 1 cm is kept in an electric field of intensity 300 V/m. Determine the energy contained in the cube of dielectric constant 8. [Given : ∈₀ = 8.85  10^–12 C^2/Nm^2]

Obtain an expression for electric field intensity at a point outside uniformly charged thin plane sheet.

Derive an expression for e.m.f. and current in terms of turns ratio

Prove theoretically  (electromagnetic induction) `e = (dphi)/(dt)`

With the help of a neat diagram, describe the construction and working of van de Graff generator.

The energy density at a point in a medium of dielectric constant 6 is 26.55 × 10⁶ J/m³. Calculate electric field intensity at that point. (ε₀ = 8.85 × 10⁻¹² SI units).

If ‘R’ is the radius of dees and ‘B’ be the magnetic field of induction in which positive charges (q) of mass (m) escape from the cyclotron, then its maximum speed (vmax) is _______.

A) `(qR)/(Bm)`

B)`(qm)/(Br)`

C) `(qBR)/m`

D) `m/(qBR)`

A transformer converts 240 V AC to 60 V AC. The secondary has 75 turns. The number of turns in primary are _______.

(A) 600

(B) 500

(C) 400

(D) 300

Define coefficient of mutual induction. 

Explain the phenomenon of mutual induction.

Write the SI unit and dimention of of co-efficient of self induction

Define the capacitance of a capacitor and its SI unit.

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?