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

A metal rod `1/sqrtpi `m long rotates about one of its ends perpendicular to a plane whose magnetic induction is 4 x 10^-3 T. Calculate the number of revolutions made by the rod per second if the e.m.f. induced between the ends of the rod is 16 mV.

A metal rod `1/sqrtpi `m long rotates about one of its ends perpendicular to a plane whose magnetic induction is 4 x 10^-3 T. Calculate the number of revolutions made by the rod per second if the e.m.f. induced between the ends of the rod is 16 mV.

State Ampere’s circuital law.

Calculate the radius of second Bohr orbit in hydrogen atom from the given data.

Mass of electron = 9.1 x 10^-31kg

Charge on the electron = 1.6 x 10^-19 C

Planck’s constant = 6.63 x 10^-34 J-s.

Permittivity of free space = 8.85 x 10^-12 C²/Nm²

State Ampere’s circuital law.

Choose the correct option.

If the pressure of an ideal gas decreases by 10% isothermally, then its volume will ______.

If the charge on the condenser of 10°F is doubled, then the energy stored in it becomes __________

Distinguish between the phenomenon of interference and diffraction of light.

The magnetic flux through a loop is varying according to a relation `phi = 6t^2 + 7t + 1` where `phi` is in milliweber and t is in second. What is the e.m.f. induced in the loop at t = 2 second?

The magnetic flux through a loop is varying according to a relation `phi = 6t^2 + 7t + 1` where `phi` is in milliweber and t is in second. What is the e.m.f. induced in the loop at t = 2 second?

Find the frequency of revolution of an electron in Bohr’s 2nd orbit; if the radius and speed of electron in that orbit is 2.14 × 10^-10 m and 1.09 × 10⁶ m/s respectively. [π= 3.142]

Draw a neat, labelled energy level diagram for H atom showing the transitions. Explain the series of spectral lines for H atom, whose fixed inner orbit numbers are 3 and 4 respectively.

The work functions for potassium and caesium are 2.25 eV and 2.14 eV respectively. Is the photoelectric effect possible for either of them if the incident wavelength is 5180 Å?

[Given : Planck’s constant = 6.63 x 10^–34 J.s.;
Velocity of light = 3 x 10⁸ m/s; 1 eV = 1.6 x 10^–19 J]

Two wires of the same material have radii rA and rB respectively. The radius of wire A is twice the radius of wire B. If they are stretched by same load then stress on wire B is _______.

If the total energy of radiation of frequency 10¹⁴ Hz is 6.63 J, calculate the number of  photons in the radiation. (Planck’s constant = 6.63 x 10^–34 J.s.)

The ratio of kinetic energy of an electron in Bohr’s orbit to its total energy in the same orbit  is

(A) – 1

(B) 2

(C) 1/2

(D) – 0.5

The body is rotating with uniform angular velocity (w) having rotational kinetic energy (E). Its angular momentum (L) is: ...............

a) `(2E)/ω`

b) `E^2/ω`

c) `E/ω^2`

d) `E/(2ω)`

A parallel beam of light travelling in water is incident obliquely on a glass surface. After refraction its width ..............

a) decreases

b) increases

c) remains the same

d) becomes zero

The kinetic energy of emitted photoelectorns is independent of ............

(a) frequency of incident radiation.

(b) intensity of incident radiation.

(c) wavelength of incident radiation

(d) collector plate potential

What is electromagnetic induction?