atomic structure

³⁰Si₁₄ and ³¹P₁₅ are

• isosteres

• isotones

• isobars

• isodiaphers

In an atom two electrons move around the nucleus in a circular orbit of radii R and 4R. The ratio of time taken by them to complete 1 revolution

• 1:4

• 4:1

• 1:8

• 8:7

In an electron microscope, electron are accelerated to great velocities. Calculate the wave length of the electron travelling with a velocity of 7.0 megameters per second. The mass of an electron is 9.1 * 10^-28 g

• 1.0 * 10^-13 m

• 1.0 * 10^-7 m

• 1.0 m

• 1.0 * 10^-10 m

• A

• B

• C

• D

An electron is moving with the velocity equal to 10% of the velocity of light. its de broglie wave length will be

• 2.4 * 10^-12 cm

• 2.4 * 10^-18 cm

• 2.4 * 10^-9 cm

• none of these

The speed of a proton is one hundreth of speed of light in vacuum. What is the DE BROGLIE wavelength? Assume that one mole of protons has a mass equal to one gram.

• 13.31 * 10^-3 A

• 1.33 * 10^-3 A

• 13.31 * 10^-2 A

• 1.31 * 10^-2 A

A green bulb and a red bulb are emitting radiations with equal power. The correct relation between number of photons emitted by the bulbs per second is

• n_g = n_r

• n_{g <} n_r

• n_{g >} n_r

• unpredictable-

According to bohrs model, the radius of Ne⁹⁺ ion in ground state should be

• 0.529 A

• 0.0529 A

• 5.29 A

• 52.9 A

The ratio of circumference of third and second orbits of He⁺ ion is

• 3:2

• 2:3

• 9:4

• 4:9

The mass of particle is 10^-10 g and its diameter is 10^-14 cm. If its speed is 10^-6 cm/s with 0.0001% uncertainty in measurement, the minimum uncertainty in its position is

• 5.28 * 10^-8 m

• 5.28 * 10^-7 m

• 5.28 * 10^-6 m

• 5.28 * 10^-9 m