Chemistry Class 11

Which of the following is never true for cathode rays?

• They possess kinetic energy

• They are electromagnetic waves

• They produce heat

• They produce mechanical pressure.

If electron travels with a velocity equal to the velocity of light its mass will be

• Zero

• Infinite

• Uncertain

• Unpredictable

The space between a proton and electron in hydrogen atom is

• Full of air

• Full of ether

• Full of electromagnetic radiations

• Empty

Which one of the following statements is wrong about photon ?

• Photon’s energy is hv

• Photon’s rest mass is zero

• Momentum of photon is hv/c

• Photon exerts no pressure

In the Bohr’s orbit , what is the ratio of total kinetic energy and total energy of the electron ?

• -1

• -2

• +1

• +2

The ionisation potential has hydrogen atom is 13.6 eV, the ionisation potential for He+ is

• 54.4 eV

• 6.8 eV

• 13.6 eV

• 24.5 eV

The one electron species having ionization energy of 54.4 eV is

• He⁺

• B⁴⁺

• Li²⁺

• Be²⁺

The radius of the first bohr orbit of hydrogen atom is 0.59 Å .The radius of the third orbit of He+ will be

• 8.46 Å

• 0.705Å

• 1.59 Å

• 2.38 Å

The ratio of ionisation energy of H and Be³⁺ is

• 1:1

• 1:3

• 1:9

• 1:16

For a d- electron ,the orbital angular momentum is

• √6 (h/2π )

• √2 (h/2π )

• (h/2π

• 2(h/2π )