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

An iron rod of the area of cross-section 0.1m² is subjected to a magnetizing field of 1000 A/m. Calculate the magnetic permeability of the iron rod. [Magnetic susceptibility of iron = 59.9, magnetic permeability of vacuum = 4π x 10^-7 S. I. unit]  

State the law of radioactive decay.

Distinguish between diamagnetic and paramagnetic substances.

Answer in brief.

State the postulates of Bohr’s atomic model.

A magnet of magnetic moment 3Am² weighs 75 g. The density of the material of the magnet is 7500 kg/m³. what is magnetization? 

What is magnetic susceptibility?

Define half-life period.

State SI unit of Magnetization.

Derive an expression for ratio of e.m.f.s and currents in terms of number of turns in primary and secondary coil.

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

An LED emits visible light when it’s ______.

Solar cell operates on the principle of ______.

Draw a neat diagram of a full-wave rectifier and explain it’s working.

Explain why the inductance of two coils connected in parallel is less than the inductance of either coil.

Define self-inductance.

Explain step up and step down transformer?

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.

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?