The angle between the incident ray and the ray reflected from the plane mirror is ${70}^{\circ }$. The angle of incidence is ​

The correct option is A ${35}^{\circ }$
According to question ,
$i+r={70}^{\circ }$
where $i$ is the angle of incidence, and
$r$ is the angle of refraction.
Feom laws of reflection,
$\text{Angle of incidence}=\text{Angle of reflection}$
$i=r$
Thus, given equation becomes
$i+i={70}^{\circ }$
$2i={70}^{\circ }$
$i={35}^{\circ }$
Angle of incidence is ${35}^{\circ }$.
Hence, option (c) is correct.