Page 115 - Physics - XII

Observations

Table for the position, nature, and size of the image formed
by concave mirror with diff erent positions of object

S. Position of
No. Object (Candle) Image (Screen) Nature and Size of Image

1. At infi nity At F Real, inverted, highly diminished

2. Beyond C Between F and C Real, inverted, diminished

3. At C At C Real, inverted, same size

4. Between F and C Beyond C Real, inverted, magnifi ed

5. At F At infi nity Real, inverted, magnifi ed, but blurred

Between F and Behind the
6. Virtual (cannot be taken on screen), erect, highly magnifi ed
P mirror

Result
The change in position, nature, and size of the image is according to the theoretical predictions.

ACTIVITY - 7

Aim

To study the nature and size of the image formed by a convex lens, on a screen by using a candle and a
screen (for diff erent distances of the candle from the lens).

Apparatus and Materials Required
A convex lens with lens holder, an optical bench with three uprights, a cardboard screen, a candle, a
matchbox, and a metre scale

B

From O F A′ 2F
Infi nity 2F F F A 2F F O

B′

(a) Object at infi nity (b) Object beyond 2F

B
B
A F A′ F 2F A′
2F F O 2F 2F A F O

B′
B′
(c) Object at 2F (d) Object between 2F and F

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