HSC Science (Electronics) इयत्ता १२ वी - Maharashtra State Board Question Bank Solutions

The ratio of diameters of two wires of the same material and length is n : 1. If the same load is applied to both the wires then increases in the length of the thin wire is ........................ (n > 1).

1. n^1/4 times
2. n^1/2 times
3. n times
4. n² times

Calculate the de Broglie wavelength of an electron moving with - of the speed of light in vacuum (Negelct relativistic effect)

(Planck's constant: h = 6.63 x 10^-34 Js, Mass of electron : m = 9.11 x 10^-28 g)

Write the functions of three segments of a transistor.

Reactance of a coil is 157 Ω. On connecting the coil across a source of frequency 100 Hz, the current lags behind e.m.f. by 45°. The inductance of the coil is ...........

(a) 0·25 H

(b) 0·5 H

(c) 4 H

(d) 314H

Electrostatic energy of 3·5 x 10^-4 J is stored in a capacitor at 700 V. What is the charge on the capacitor?

Intensity of electric field at a point close to and outside a charged conducting cylinder is proportional to ______. (r is the distance of a point from the axis of cylinder)

(A) `1/r`

(B) `1/r^2`

(C) `1/r^3`

(D) r³

A mass of 1 kg is hung from a steel wire if radius 0.5 mm and length 4 m. Calculate the extension produced. What should be the area of cross-section of the wire so that elastic  limit is not exceeded? Change in radius is negligible

(Given : g = 9.8 m/s^2; Elastic limit of steel is 2.4 x 10⁸ N/m²;Y for steel (Ysteel) = 20 x 10¹⁰ N/m²; π = 3.142)

In Doppler effect of light, the term “red shift” is used for ______.

(A) frequency increase

(B) frequency decrease

(C) wavelength decrease

(D) frequency and wavelength increase

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]

Doppler effect is not applicable when _______.
(A) source and observer are at rest.
(B) there is a relative motion between source and observer.
(C) both are moving in opposite directions.
(D) both are moving in same direction with different velocities

Three capacitors of capacities 8 μF, 8 μF and 4 μF are connected in a series and potential difference of 120 volt is maintained across the combination. Calculate the charge  on capacitor of capacity 4 μF.

The working of RADAR is based on ...............

a) resonance

b) speed of a star

c) Doppler effect

d) speed of rotation of sun

Write the necessary equation for maximum safety, speed and state the significance of each term involved in it.

A point is situated at 6.5 em and 6.65 em from two coherent sources. Find the nature of illumination at the point, if wavelength of light is 5000 Å

Apparent frequency of the sound heard by a listener is less than the actual frequency of sound emitted by source. In this case _______.

(A) listener moves towards source

(B) source moves towards listener

(C) listener moves away from the source.

(D) source and listener move towards each other.

Explain the need for modulation related to the size of antenna (aerial).

Draw a circuit diagram for studying the input and output characteristics of a n-p-n transistor in common emitter configuration. Using the circuit, explain how input, output characteristics are obtained

State any four applications of Doppler effect

A falt curve on a highways has a radius of curvature 400 m. A car goes around a curve at a speed of 32 m/s. What is the minimum value of the coefficient of friction that will prevent the car from sliding? (g = 9.8 m/s²)

A capacitor of capacitance 0.5 μF is connected to a source of alternating e.m.f. of frequency 100 Hz. What is the capacitive reactance? (Π = 3.142)