By applying Pythagoras theorem,
\((15)^2= (12)^2 + a^2\)
\(225 = 144 + a^2\)
\(a^2 =225 - 144 = 81\)
\(a = 9\;m\)
Therefore, the distance of the foot of the ladder from the wall is \(9\) \(m\).
Match the items given in Column I with one or more items of Column II.
Column I | Column II |
(a) A plane mirror | (i) Used as a magnifying glass. |
(b) A convex mirror | (ii) Can form image of objects spread over a large area. |
(c) A convex lens | (iii) Used by dentists to see enlarged image of teeth. |
(d) A concave mirror | (iv) The image is always inverted and magnified. |
(e) A concave lens | (v) The image is erect and of the same size as the object. |
- | (vi) The image is erect and smaller in size than the object. |