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

The kinetic energy of nitrogen per unit mass at 300 K is 2.5 × 106 J/kg. Find the kinetic energy of 4 kg oxygen at 600 K. (Molecular weight of nitrogen = 28, Molecular weight of oxygen = 32)

A galvanometer has a resistance of 16Ω. It shows full scale deflection, when a current of 20 mA is passed through it. The only shunt resistance available is 0.06  which is not appropriate to convert a galvanometer into an ammeter. How much resistance should be connected in series with the coil of galvanometer, so that the range of ammeter is 8 A?

Show that only odd harmonics are present in an air column vibrating in a pipe closed at one end.

A stretched wire emits a fundamental note of frequency 256 Hz. Keeping the stretching force constant and reducing the length of wire by 10 cm, the frequency becomes 320 Hz. Calculate the original length of wire.

Explain two types of diffraction of light.

What is Zener diode?

Define the capacitance of a capacitor and its SI unit.

Obtan an expression for potential energy of a particle performing S.H.M. What is the value of potential energy at (i) Mean position, and (ii) Extreme position

Monochromatic light of wavelength 4300 Å falls on a slit of width ‘a’. For what value of ‘a’ the first maximum falls at 30° ?

A parallel plate air condenser has a capacity of 20µF. What will be a new capacity if:

1) the distance between the two plates is doubled?

2) a marble slab of dielectric constant 8 is introduced between the two plates?

State how a moving coil galvanometer can be converted into an ammeter.

Answer in brief:

State the conditions under which the theorems of parallel axes and perpendicular axes are applicable. State the respective mathematical expressions.

On what factors do the degrees of freedom depend?

Answer in brief.

What does the hysteresis loop represent?

State the law of equipartition of energy and hence calculate the molar specific heat of mono-atomic and di-atomic gases at constant volume and constant pressure.

In a Faraday disc dynamo, a metal disc of radius R rotates with an angular velocity ω about an axis perpendicular to the plane of the disc and passing through its center. The disc is placed in a magnetic field B acting perpendicular to the plane of the disc. Determine the induced emf between the rim and the axis of the disc.

A horizontal wire 20 m long extending from east to west is falling with a velocity of 10 m/s normal to the Earth’s magnetic field of 0.5 × 10⁻⁴ T. What is the value of induced emf in the wire?

A stiff semi-circular wire of radius R is rotated in a uniform magnetic field B about an axis passing through its ends. If the frequency of rotation of wire is f, calculate the amplitude of alternating emf induced in the wire.

Show that in an AC circuit containing a pure inductor, the voltage is ahead of current by π/2 in phase.

Which property of light does not change when it travels from one medium to another?