A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle, screen and the lens as under
Position of candle `= 12.0 cm`
Position of convex lens `= 50.0 cm`
Position of the screen `= 88.0 cm`
(i) What is the focal length of the convex lens ?
(ii) Where will the image be formed if he shifts the candle towards the lens at a position of `31.0 cm`.
(iii) What will be the nature of the image formed if he further shifts the candle towards the lens ?
(iv) Draw a ray diagram to show the formation of the image in case (iii) as said above.

Rohit focused the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle, screen and lens as under: Position of candle = 26.0 cm Position of convex lens = 50.0 cm Position of screen=74.0 cm (i) What is the focal length of the convex lens ? (ii) Where will the image be formed if he shifts the candle towards the lens at a position of 38 cm ? (iii) Draw a ray diagram to show the formation of the image in case (ii) as said above?

Rohit focussed the image of a candle flame on a white screen using a convex lens. He noted position of candle = 26.0 cm , position of convex lens = 50.0 cm and position of screen = 74.0 cm . (i) What is focal length of convex lens? (ii) Where will the image be formed if he shifts the candle towards the lens at a position of 38 cm ? (iii) Draw a ray diagram to show the formation of image in (ii) above.

A student focussed the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations as : What type of lens is a convex lens?

A student focussed the flame of a candle on a screen with the help of a convex lens. He noted the positions of candle, lens and screen on the scale as given below: Position of candle = 14.0 cm, Position of convex lens = 50.0 cm, Position of screen = 86.0 cm (i) Find the focal length of the lens. (ii) If under the given condition, height of the flame is 1.5 cm, what would be the height of image obtained on the screen? (iii) If he displaces the candle to 32.0 cm, where will the image be formed and what will be its nature? Give reason for your answer. (iv) After this if he further displaces the candle towards the lens, what will be the nature of the image formed and where will it be? (v) Draw a ray diagram to show the formation of image in the above mentioned case. [Hints. (i) u = (50-14) cm = 36 cm, v = (86 - 50) cm = 36 cm. Thus the object is at 2f. Therefore f = 18cm (ii) Height will be same, i.e., 1.5 cm (iii) u = 50-32 = 18 cm. Thus, object will be at focus. Therefore, image will be at infinity and is real, inverted and enlarged. (iv) Object will come in between focus and optical centre. Image will be virtual, erect and enlarged and formed on the same side of lens as the object.

A student focussed the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations as : Which set of observations is incorrect?

A student focussed the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations as : In which case, the size of the object and image will be same?