(a) Ratio of father’s present age to that of son =\(\frac{ 42}{14}\)
\(= \frac{3}{1}\)
\(= 3:1\)
(b) When son was 12 years, i.e., 2 years ago, then father was (42 – 2) = 40 years
Therefore, the ratio of their ages = \(\frac{40}{12}\)
\(=\frac{ 10}{3}\)
\(= 10:3\)
(c) Age of father after 10 years = 42 + 10 = 52 years
Age of son after 10 years = 14 + 10 = 24 years
Therefore, ratio of their ages =\( \frac{52}{24}\)
\(= \frac{13}{6}\)
\(= 13:6\)
(d) When father was 30 years old, i.e., 12 years ago, then son was (14 – 12) = 2 years old
Therefore, the ratio of their ages =\(\frac{ 30}{2}\)
\(= \frac{15}{1}\)
\(= 15:1\)
Complete the drawing shown in Fig. 9.14 to indicate where the free ends of the two wires should be joined to make the bulb glow