A candle flame of 3 cm is placed at 300 cm from a wall. A concave mirror is kept at distance x from the wall in such a way that image of the flame on the wall is 9 cm. Then x is -

A convex lens of power 4 D is placed at a distance of 40 cm from a wall . At what distance from the lens should a candle be placed so that its image is formed on the wall ?

A convex lens of power 4D is placed at a distance of 40 cm from a wall at what distance from the lens should a candle be placed so that its image is formed on the wall?

A 2.5 cm high candle flame is placed at a distance of 2.5 m from a wall. How far from the wall a concave mirror must be placed so that a 7.5 cm high inverted image of the flame is formed on the same wall? Also calculate the focal length of the mirror.

A candle flame 2 cm high is placed at distance of 2 meter from a wall. How far from the wall must a concave mirror to placed in order to form an image of the flame 6 cm high on the wall ?

A candle flame 2 cm high is placed at distance of 2 meter from a wall. How far from the wall must a concave mirror to placed in order to form an image of the flame 6 cm high on the wall ?

A candle is flame 1 cm high is placed at a distance of 1.5 metre from a wall.How far from the wall must a concave mirror be placed ,so that it may form a 2 cmhigh image of the flame on the flame on the same wall?Also find the focal length of the mirror.