HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

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)

Calculate the de-Broglie wavelength of an electron moving with one-fifth of the speed of light.Neglect relativistic effects. (`h = 6.63 xx 10^(-34)` J.s, c= `3xx10^8`m/s, mass of electron = `9 xx 10^(-31) kg)`

An electron of energy 150 eV has wavelength of 10^-10m. The wavelength of a 0.60 keV electron is?

Answer in brief:

What is a perfect blackbody? How can it be realized in practice?

During refrigeration cycle, heat is rejected by the refrigerant in the ______.

A gas contained in a cylinder surrounded by a thick layer of insulating material is quickly compressed has there been a transfer of heat?

Answer in brief:

A gas contained in a cylinder surrounded by a thick layer of insulating material is quickly compressed has work been done?

A resistor of 500 Ω and an inductance of 0.5 H are in series with an AC source which is given by V = `100 sqrt2` sin (1000 t). The power factor of the combination is ______.

In a series LCR circuit, the phase difference between the voltage and the current is 45°. Then the power factor will be ______.

What is wattles current?

When an AC source is connected to an ideal inductor show that the average power supplied by the source over a complete cycle is zero.