HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Important Questions

The magnetic flux through a loop varies according to the relation Φ = 8t² + 6t + 2, Φ is in milliweber and t is in second. What is the magnitude of the induced emf in the loop at t = 2 seconds?  

Explain step up and step down transformer?

Determine the motional emf induced in a straight conductor moving in a uniform magnetic field with constant velocity on the basis of Lorentz force.

The primary of a transformer has 40 turns and works on 100 V and 100 W. Find a number of turns in the secondary to step up the voltage to 400 V. Also calculate the current in the secondary and primary.

Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire. 

Describe the construction and working of a transformer with a neat labelled diagram.

State the advantages of potentiometer over voltmeter.

Define potential gradient of the potentiometer wire.

How is potential gradient measured? Explain.

Distinguish between a potentiometer and a voltmeter.

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

Four resistances 6Ω, 6Ω, 6Ω and 18Ω form a Wheatstone bridge. Find the resistance which connected across the 18Ω resistance will balance the network.

Explain with a neat circuit diagram. How you will determine the unknown resistances using a meter bridge.

A cell of e.m.f 1.5V and negligible internal resistance is connected in series with a potential meter of length 10 m and the total resistance of 20 Ω. What resistance should be introduced in the resistance box such that the potential drop across the potentiometer is one microvolt per cm of the wire?  

State any two characteristics of a series LCR AC resonance circuit.

Find the current in a circuit consisting of a coil and a capacitor in series with an A.C source of 110V (r.m.s.), 60Hz. The inductance of a coil is 0.80 H and its resistance is 50Ω. The capacitance of a capacitor is 8µF. 

A radio can tune over the frequency range of a portion of the MW broadcast band (800kHz -1200kHz). If its LC circuit has an effective inductance of 200mH, what must be the range of its variable condenser? 

If the frequency of incident light falling on a photosensitive material is doubled, then the kinetic energy of the emitted photoelectron will be ______.

Which one of the following particles cannot be accelerated by a cyclotron?

(A) Electrons

(B) Protons

(C) Deuterons

(D) α- particles

State Ampere’s circuital law.