If L is the coherence length and c the velocity of light, the coherent time is 

(1) cL

(2) $\frac{L}{c}$

(3) $\frac{c}{L}$

(4) $\frac{1}{Lc}$

For constructive interference to take place between two monochromatic light waves of wavelength λ, the path difference should be 

(1) $(2n-1)\frac{\lambda }{4}$

(2) $(2n-1)\frac{\lambda }{2}$

(3) $n\lambda$

(d) $(2n+1)\frac{\lambda }{2}$

Soap bubble appears coloured due to the phenomenon of:
1. Interference
2. Diffraction
3. Dispersion
4. Reflection

Which of the following statements indicates that light waves are transverse? 

Interference was observed in interference chamber when the air was present, now the chamber is evacuated and if the same light is used, a careful observer will see

(1) No interference

(2) Interference with bright bands

(3) Interference with dark bands

(4) Interference in which width of the fringe will be slightly increased

Two coherent sources have intensity in the ratio of $\frac{100}{1}$. Ratio of (intensity)_max/(intensity)_min is: 
1. $\frac{1}{100}$
2. $\frac{1}{10}$
3.$\frac{10}{1}$
4. $\frac{3}{2}$

If two waves represented by $y_1=4\sin \omega t$ and $y_2=3\sin \left(\omega t+\frac{{\displaystyle \pi }}{{\displaystyle 3}}\right)$ interfere at a point, the amplitude of the resulting wave will be about 

(1) 7

(2) 6

(3) 5

(4) 3.5

Two coherent sources of intensities, I₁ and I₂ produce an interference pattern. The maximum intensity in the interference pattern will be 

(1) I₁ + I₂

(2) $I_1^2+I_2^2$

(3) (I₁ + I₂)²

(4) ${(\sqrt{I_1}+\sqrt{I_2})}^2$

Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{\pi }{2}$ at point A and π at point B. Then the difference between the resultant intensities at A and B is 

(1) 2I

(2) 4I

(3) 5I

(4) 7I

If an interference pattern has maximum and minimum intensities in a 36 : 1 ratio, then what will be the ratio of their amplitudes?

1. 5 : 7

2. 7 : 4

3. 4 : 7

4. 7 : 5