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

How is the magnetic field of a small current loop identical to that of a short magnetic dipole? Explain.

Two coils having self inductances L₁ = 75 mH and L₂ = 55 mH are coupled with each other. The coefficient of coupling (K) is 0. 75. Calculate the mutual inductance (M) of the two coils

State and explain Stefan's law of radiation.

Define Boltzmann constant.

Calculate the amount of energy evolved when 343 droplets of mercury each of radius. 0.05 mm, combine to form one drop. The surface tension of mercury is 50 x 10^-2 N/m.

Calculate the values of x and y in the following nuclear reaction.

\[\ce{^227_89Ac -> ^211_82Pb + x[^4_2He]+ y[^0_-1e]}\]

What is binding energy of nucleus?

What is binding energy of a hydrogen atom?

Define the surface energy of the liquid.

State the principle on  which transformer works.

Explain the construction and working of the transformer. 

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

Explain Maxwell distribution of molecular speed with necessary graph.

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

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

What is gamma decay?

Sample of carbon obtained from any living organism has a decay rate of 15.3 decays per gram per minute. A sample of carbon obtained from very old charcoal shows a disintegration rate of 12.3 disintegrations per gram per minute. Determine the age of the old sample given the decay constant of carbon to be 3.839 × 10⁻¹²per second.

The primary and secondary coils of a transformer each have an inductance of 200 x 10^-6 H. The mutual inductance between the windings is 4 x 10^-6 H. What percentage of the flux from one coil reaches the other?

A circular coil of 100 turns with a cross-sectional area of 1 m² is kept with its plane perpendicular to the magnetic field of 1 T. The magnetic flux linkage is ______.

Describe alpha, beta and gamma decays and write down the formulae for the energies generated in each of these decays.