Question

HELLO GUYS.. PLS ANSWER THIS QUESTION. I WILL SURELY MARK U AS BRAINLIEST A concave mirror produces a three times magnified image on a screen. If the object is placed 20 cm in front of the mirror, how far is the screen from the object?

Answer 1

$\underline {\huge{ \red{SOLUTION:-}}}$

$\bold{Magnification}$

$\boxed{ \bold{m = -v/ u}}$

If we assume image is real and inverted then, u and v both will be negative.

$\rightarrow \: {-3 = -v/-20}$

$\boxed{v = - 60 cm}$

However, if we assume image to be virtual and erect then magnification will be positive. Then

$\rightarrow \: {3 = -v/-20}$

$\boxed{v = 60 cm}$

Answer 2

$\huge{ \underline{\underline{ \fcolorbox{white}{black}{\sf{answer : - }}}}}$

v=u+at

a=(v-u)/t -----------(1)

v=72 km/h

=20m/s

u=0

t=5*60 sec =300sec

by putting values of v,u,t in (1)

a=1/15 m/s2

s=ut +(1/2)at2

=0+(1/2)(1/15)(300)(300)

=3km