Physics 2nd Paper MCQ-Dinajpur Board-2017

1. The path difference between two points of a wave is $\frac{5 \lambda}{4}$. Their phase difference is-

2. When is entropy the least?

3. The distance between two charges in air of-4 $\mathrm{C}$ and $5 \mathrm{C}$ is infinite. The functional force is -

4. The half-life of Radon is 4 days. Its average life is-

(a) 5.77 days

(b) 4.33 days

5. Focus distance of lens with +5Dpower is-