Mark True or False

1. Mirror formula $\frac{1}{f}=\frac{1}{u}+\frac{1}{v}$ does not hold good for plane mirror.

2. R = 2f is valid only when paraxial rays are considered.

3. Similarity of $∆APB and ∆A\text{'}PB\text{'}$ proves $\frac{h}{h\text{'}}=\frac{v}{u}$ where promumerals has conventional connotation.

4. In case of convex mirror focal length is always +ve.

If a mirror forms erect image for objects placed between pole and focus, and it forms real-inverted image for object placed anywhere between focus and infinity, then the mirror is:

In the following diagram ‘$M$’ is a mirror and ‘$P$’ is an object and ‘$Q$’ is the magnified image of ‘$P$’ formed by the mirror. The mirror ‘$M$’ is a:

Which effect is responsible for blue colour of smoke?

A concave mirror of focal length 15cm forms an image. The position of the object when the image is virtual and linear magnification is 2 is.

Correct relation between radius of curvature($R$) and Focal length ($F$) of a spherical mirror is:

Focal length of one convex mirror is $3 \mathrm{m}$ and object distance is $5 \mathrm{m}$, then find the image distance.

($F =$ principal focus, $C =$centre of curvature, $P =$ pole)