Current Electricity Charging Discharging Of Capacitors Question 730
Question: A electric tea kettle has two heating coils. When first coil of resistance $ R _{1} $ is switched on, the kettle begins to boil tea in 6 minutes. When second coil of resistance $ R _{2} $ is switched on, the boiling begins in 8 minutes. The value of $ R _{1}/R _{2} $ is
Options:
A) $ \frac{7}{3} $
B) $ \frac{3}{7} $
C) $ \frac{3}{4} $
D) $ \frac{4}{3} $
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Answer:
Correct Answer: C
Solution:
[c] Heat supplied $ =\frac{V^{2}}{R}\times t $
$ \Rightarrow \frac{t _{1}}{R _{1}}=\frac{t _{2}}{R _{2}}\Rightarrow \frac{6}{R _{1}}=\frac{8}{R _{2}}\Rightarrow \frac{R _{1}}{R _{2}}=\frac{3}{4} $
BETA
