Atoms — Physics STD 12 Science — Question

Coulomb's Law agrees with________?

Assertion :   The specific charge for positive rays is a characteristic constant.

Reason     : The specific charge depends on charge and mass of positive ions present in positive rays.

(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.

Which of the following rays are not electromagnetic waves

(a) g-rays

(b) b-rays

(c) Heat rays

(d) X-rays

In photoelectric effect, the K.E. of electrons emitted from the metal surface depends upon

(a) Intensity of light	(b) Frequency of incident light
(c) Velocity of incident light	(d) Both intensity and velocity of light

A parallel plate air capacitor has capacity ′C′ farad, potential ′V′ volt and energy ′E′ joule. When the gap between the plates is completely filled with dielectric.

The energy of characteristic X-ray is a consequence of which of the following?

In hydrogen atom, if the difference in the energy of the electron in n = 2  and n = 3  orbits is E, the ionization energy of hydrogen atom is

(a) 13.2 E

(b) 7.2 E

(c) 5.6 E

(d) 3.2 E

In the following diagram the work done in moving a point charge from point P to point A, B and C is respectively as W_A, W_B and W_C , then

(a) WA = WB = WC

(b) WA = WB = WC = 0

(c) WA > WB > WC

(d) WA < WB < WC