Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

The pressure of a gas kept in an isothermal container is 200kPa. If half the gas is removed from it, the pressure will be:

1. 100kPa.
2. 200kPa.
3. 400kPa.
4. 800kPa.

The work-function of a metal is:

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line

(a) 0o

(b) 90o

(c) 180o

(d) None of these

The radius of a metallic sphere if its capacitance is 1/9 F, is

(a)

(b)

(c)

(d)

Assertion   :   A metallic shield in form of a hollow shell may be built to block an electric field.

Reason       : In a hollow spherical shield, the electric field inside it is zero at every point.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Work function of lithium and copper are respectively 2.3 eV and 4.0 eV. Which one of the metal will be useful for the photoelectric cell working with visible light ? (h = 6.6 × 10^–34 J-s, c = 3 × 10⁸ m/s)

(a) Lithium

(b) Copper

(c) Both

(d) None of these

The property which differentiate the two kinds of charges is called as:

The kinetic energy of an electron with de-Broglie wavelength of 0.3 nanometer is

(a) 0.168 eV

(b) 16.8 eV

(c) 1.68 eV

(d) 2.5 eV

The effective length of a magnet is 31.4 cm and its pole strength is 0.5 Am. The magnetic moment, if it is bent in the form of a semicircle will be

(a)

(b)

(c)

(d)