Which of the following has greater number of electrons than neutrons?

1. Al³⁺

2. O^2-

3. F^-

4. C

The work function of a metal is 4.2 eV. If radiations of 2000 $A^0$ fall on the metal then the kinetic energy of the fastest photoelectron is 

1. 1.6 x 10^-19J 

2. 16 x 10¹⁰J 

3. 3.2 x 10^-19J 

4. 6.4 x 10^-10J 

 The relationship between the energy \(E_1\) of radiation with a wavelength of \(8000\) Å and the energy \(E_2\)​ of radiation with a wavelength of \(16000\) Å is:

1. \(E_1=6E_2\)
2. \(E_1=2E_2\)
3. \(E_1=4E_2\)
4. \(E_1=1 / 2 E_2\)

The transition of electrons in H atom that will emit maximum energy is:

1. n₃ $\to$ n₂

2. n₄ $\to$ n₃

3. n₅ $\to$ n₄

4. n₆ $\to$ n₅

The transition in the He⁺ ion in the balmer series that would have the same wave number as the first Lyman line in the hydrogen spectrum is-

If the speed of electron in Bohr's first orbit of hydrogen atom be x, then speed of the electron in 3rd orbit is:

1. x/9

2. x/3

3. 3x

4. 9x

In Bohr's model of the hydrogen atom the ratio between the period of revolution of an electron in the orbit n=1 to the period of revolution of the electron in the orbit n=2 is

1. 1:2

2. 2:1

3. 1:4

4. 1:8

A cricket ball of 0.5 kg is moving with a velocity of 100 ms^-1. The wavelength associated with its motion is:

1. 1/100cm

2. 6.6 x 10^-34m

3. 1.32 x 10^-35m

4. 6.6 x 10^-28m

The number of electrons in  ₁₉ K with quantum numbers n=3; l=0 is/are:

1. 2

2. 1

3. 4

4. 3

The ratio of the difference in energy between the first and second Bohr orbit of H to that between the second and the third Bohr orbit is 

1. 1/2

2. 1/3

3. 4/9

4. 27/5