HSC Science (Electronics) इयत्ता १२ वी - Maharashtra State Board Question Bank Solutions for Physics

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?

What is electromagnetic induction?

Prove theoretically  (electromagnetic induction) `e = (dphi)/(dt)`

Prove theoretically  (electromagnetic induction) `e = (dphi)/(dt)`

Answer in brief:

Derive an expression for the period of motion of a simple pendulum. On which factors does it depend?

If ‘L’ is the angular momentum and ‘I’ is the moment of inertia of a rotating body, then `L^2/(2I)`represents its _____

(A) rotational P.E.

(B) total energy

(C) rotational K.E.

(D) translational K.E

If ‘R’ is the radius of dees and ‘B’ be the magnetic field of induction in which positive charges (q) of mass (m) escape from the cyclotron, then its maximum speed (vmax) is _______.

A) `(qR)/(Bm)`

B)`(qm)/(Br)`

C) `(qBR)/m`

D) `m/(qBR)`

If ‘R’ is the radius of dees and ‘B’ be the magnetic field of induction in which positive charges (q) of mass (m) escape from the cyclotron, then its maximum speed (vmax) is _______.

A) `(qR)/(Bm)`

B)`(qm)/(Br)`

C) `(qBR)/m`

D) `m/(qBR)`

Obtain an expression for magnetic induction along the axis of the toroid.

If the source is moving away from the observer, then the apparent frequency _____.

(a) will increase

(b) will remain the same

(c) will be zero

(d) will decrease