Chat with tutor

Ask Questions, Get Answers

Questions  >>  CBSE XII  >>  Physics  >>  Current Electricity

An electric kettle has two coils. When one of these is switched on, the water in the kettle boils in 6 minutes. When the other coil is switched on, the water boils in 3 minutes. If the two coils are connected in parallel , find the time taken to boil the water in the kettle .

$\begin{array}{1 1} 2\;m \\ 10\;m \\ 100\;s \\ 10\;mins \end{array} $

1 Answer

Solution :
The effective resistance when connected in parallel is
$R^1= \large\frac{R_1R_2}{R_1+R_2}$
$\qquad= \large\frac{2 R_2 \times R_2}{2R_2 +R_2}=\frac{2}{3}$$R_2$
$\bigg[ \large\frac{R_1}{R_2} $$=2 \;or\; R_1 =2 R_2 \bigg]$
$\large\frac{2/3 R_2}{R_2} =\frac{t^1}{3}$$=2 minutes$
Answer : 2m
Help Clay6 to be free
Clay6 needs your help to survive. We have roughly 7 lakh students visiting us monthly. We want to keep our services free and improve with prompt help and advanced solutions by adding more teachers and infrastructure.

A small donation from you will help us reach that goal faster. Talk to your parents, teachers and school and spread the word about clay6. You can pay online or send a cheque.

Thanks for your support.
Please choose your payment mode to continue
Home Ask Homework Questions
Your payment for is successful.
Clay6 tutors use Telegram* chat app to help students with their questions and doubts.
Do you have the Telegram chat app installed?
Already installed Install now
*Telegram is a chat app like WhatsApp / Facebook Messenger / Skype.