The wavelength of an electron moving with a velocity of 2.05 × 10⁷ m s^–1  would be:  

\(1 .\) \(4 . 65\) \(\times\) \(10^{- 12}\) \(m\)

\(2 .\) \(3 . 55\) \(\times\) \(10^{-11}\) \(m\)

\(3 .\) \(2 . 34\) \(\times\) \(10^{11}\) \(m\)

\(4 .\) \(6 . 43\) \(\times\) \(10^{ -11}\) \(m\)

Determine the wave length of an electron if its kinetic energy is \(3.0 \times 10^{-25}~ \mathrm J\):
1. \(8.96 \times 10^{-7}~ \mathrm m\)
2. \(4.37 \times 10^{-6}~ \mathrm m\)
3. \(1.32 \times 10^{-7}~ \mathrm m\)
4. \(2.89 \times 10^{-4}~ \mathrm m\)

The lowest value of n for 'g' orbitals is :

A neutral atom contains 29 electrons and 35 neutrons. Determine the number of protons present in the element.

How many carbon atoms of diameter 0.15 nm can be placed side by side to form a straight line of length 20 cm?$\mathrm{}$

An oil drop carries a negative charge of −1.282 × 10⁻¹⁸ C. Calculate the number of excess electrons present on the oil drop.

1. Fifteen (15)

2. Eight (8)

3. Two (2)

4. Six (6)

An atom has a mass number of 81 and contains 31.7% more neutrons than protons. Which of the following represents the correct atomic symbol of the element?

$1.$ ${}_{35}{}^{81}\mathrm{Br}$
$2.$ ${}_{36}{}^{81}\mathrm{Br}$
$3.$ ${}_{35}{}^{79}\mathrm{Br}$
$4.$ ${}_{36}{}^{79}\mathrm{Br}$

A tripositive ion has a mass number of 56 and contains 30.4% more neutrons than electrons. Which of the following correctly represents the symbol of the ion?

$1.$ ${}_{26}{}^{56}\mathrm{Fe}^{+3}$
$2.$ ${}_{26}{}^{57}\mathrm{Fe}^{+3}$
$3.$ ${}_{27}{}^{58}\mathrm{Fe}^{+3}$
$4.$ ${}_{25}{}^{56}\mathrm{Fe}^{+3}$

The wavelength of radiation emitted by a nitrogen laser is 337.1 nm. Calculate its power if the photon emission rate is 5.6 × 10²⁴ s⁻¹.

$\mathrm{}$$1.$ $4.56$ $\times$ ${10}^7$ $\mathrm{J}$
$2.$ $3.33$ $\times$ ${10}^6$ $\mathrm{J}$
$3.$ $1.29$ $\times$ ${10}^6$ $\mathrm{J}$
$4.$ $9.17$ $\times$ ${10}^5$ $\mathrm{J}$

A photon detector receives a total energy of \(3.15 \times 10^{-18}\) J from radiation with a wavelength of 600 nm. How many photons are received by the detector?

$1.$ ${10}^2$
$2.$ $10$
$3.$ $50$
$4.$ $20$