Images formed by an object placed between two plane mirrors whose reflecting surfaces make an angle of $90^o$ with one another lie on

It is desired to photograph the image of an object placed at a distance of $3\;m$ from a plane mirror. The camera,which is at a distance of $4.5\;m$ from the mirror,should be focused for a distance of......$m$.

$A$ girl of height $150 \,cm$ with her eye level at $140 \,cm$ stands in front of a plane mirror of height $75 \,cm$ fixed to a wall. The lower edge of the mirror is at a height of $85 \,cm$ above her feet level. The height of her image the girl can see in the mirror is (in $cm$)

$A$ man runs towards a plane mirror at a speed of $15 \, m/s$. The speed of the image relative to the man is $...... \, m/s$.

Two plane mirrors are inclined to one another at an angle of $60^o$. $A$ ray is incident on mirror $M_1$ at an angle $i$. The reflected ray from mirror $M_1$ is shown in the figure. The angle of incidence $i$ is (in $^o$)

An object is initially at a distance of $100 \; cm$ from a plane mirror. If the mirror approaches the object at a speed of $10 \; cm/s$,then after $6 \; s$,the distance between the object and its image will be: (in $; cm$)