What is the EAN of [Al(C₄O₄)₃]^3- ?

• 28

• 22

• 16

• 10

An isobar of ₂₀C⁴⁰ is

• ₁₈Ar⁴⁰

• ₂₀Ca³⁸

• ₂₀Ca⁴²

• ₁₈Ar³⁸

63.

In successive emission of $\mathrm{\alpha }$-and $\mathrm{\beta }$-particles, the number of $\mathrm{\alpha }$-and $\mathrm{\beta }$-particles should be emitted for the conversion of ₉₂U²³⁸ to ₈₂P²⁰⁶ are

• $7\mathrm{\alpha }, 5\mathrm{\beta }$

• $6\mathrm{\alpha }, 4\mathrm{\beta }$

• $4\mathrm{\alpha }, 3\mathrm{\beta }$

• $8\mathrm{\alpha }, 6\mathrm{\beta }$

An element _xA^y emits 5 α and 4β particles to give ₈₂B²⁰⁷. The number of protons and neutrons in A are respectively

• 88, 227

• 88, 139

• 82, 227

• 84, 139

Which of the following has the maximum penetrating power ?

• $\mathrm{\alpha }-$ particle

• $\mathrm{\gamma }-$particles

• Proton

• Positron

Which of the following travels with the speed of light?

• α-rays

• β-rays

• γ-rays

• X-rays

4 L- atom is equal to

• 40.50 cal

• 78.75 cal

• 95.23 cal

• 96 cal

₉₀Th²²⁸ emits four alpha and one beta particles. Number of neutrons in daughter element is

• 129

• 190

• 232

• 138

Which of the ions is colourless inspite of the presence of unpaired electrons ?

• La³⁺

• Eu³⁺

• Gd³⁺

• Lu³⁺

Uncertainty in the position of an electron (mass= 9.1 x 10^-31 kg) moving with a velocity 300 ms^-1 accurate upon 0.001 % will be (h = 6.63 x 10^-34 J-s)

• 19.2 x 10^-2 m

• 5.76 x 10^-2 m

• 1.92 x 10^-2 m

• 3.84 x 10^-2 m