Question

when parallel beam of sun rays fall on a concave mirror and reflect they meet at answer


​

Answer 1

${\huge{\boxed{\mathscr{\pink{Answer::}}}}}$

Sun is at infinite distance from the surface of the earth. Now light rays from sun rays after reflection from concave mirror will converge at focus. It is given that sunrays converge at 15 cm. So, focal length of the mirror = f = 15 cm.

Answer 2

$\huge \sf \blue {\underline{\red{Answer :-}}}$

Sun is at infinite distance from the surface of the earth. Now light rays from sun rays after reflection from concave mirror will converge at focus. It is given that sunrays converge at 15 cm. So, focal length of the mirror = f = 15 cm.