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

A circular coil of 250 turns and diameter 18 cm carries a current of 12A. What is the magnitude of magnetic moment associated with the coil?

Draw a neat labelled diagram for Davisson and Germer experiment, for diffraction of electron wave.

An ideal voltmeter has _______.

(A) low resistance

(b) high resistance

(C) infinite resistance

(D) zero resistance

If a watch-glass containing a small quantity of water is placed on two dissimilar magnetic poles, then water ______.

Explain how moving coil galvanometer is converted into a voltmeter. Derive the necessary formula.

A rectangular coil of a moving coil galvanometer contains 100 turns, each having area
15 cm². It is suspended in the radial magnetic field 0.03 T. The twist constant of suspension
fibre is 15 x 10^-10 N-m/degree. Calculate the sensitivity of the moving coil galvanometer.

The fraction of the total current passing through the galvanometer is ............ .

a) `S/(S+G)`

b) `G/(S+G)`

c) `(S+G)/G`

d) `(S+G)/S`

A moving coil galvanometer has a resistance of 25Ω and gives a full scale deflection for a current of 10mA. How will you convert it into a voltmeter having range 0 - 100 V?

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?

Explain Ampere’s circuital law.

A cyclotron is used to accelerate protons to a kinetic energy of 5 MeV. If the strength of magnetic field in the cyclotron is 2T, find the radius and the frequency needed for the applied alternating voltage of the cyclotron. (Given : Velocity of proton= `3xx10^7 m//s`)

A photocell is used to automatically switch on the street lights in the evening when the sunlight is low in intensity. Thus it has to work with visible light. The material of the cathode of the photocell is ______.

What is the photoelectric effect?

The threshold wavelength of tungsten is 2.76 x 10^-5 cm.
(a) Explain why no photoelectrons are emitted when the wavelength is more than 2.76 x 10^-5 cm.
(b) What will be the maximum kinetic energy of electrons ejected in each of the following cases

(i) if ultraviolet radiation of wavelength λ = 1.80 × 10^-5 cm and
(ii) radiation of frequency 4 x 10¹⁵ Hz is made incident on the tungsten surface?

What do you understand by the term wave-particle duality? Where does it apply?

According to De-Broglie, the waves are associated with ______ 

Planck's constant is 6.6 × 10^-34 Js. The momentum of each photon is given radiation Is 3.3 × 10^-29 kg/s. The λ of radiation is ______.

Define photoelectric effect. 

The minimum frequency for photoelectric effect on metal is 7 × 10¹⁴ Hz, Find the work function of the metal. 

If the total energy of radiation of frequency 10¹⁴ Hz is 6.63 J, Calculate the number of photons in the radiation.