Email
Chat with tutor
logo

Ask Questions, Get Answers

X
 
Questions  >>  CBSE XII  >>  Physics  >>  Alternating current
Answer
Comment
Share
Q)

An electric motor operation on a $50\;v$ d.c supply draws a current of $12\;A$ . If the efficiency of the motor is $30\%$ , estimate the resistance of the motor .

$\begin{array}{1 1} 30 \;\Omega \\ 0.3\;\Omega \\ 3\;\Omega \\ 0.03\; \Omega \end{array} $

1 Answer

Comment
A)
Solution :
given $V= 50\;V$
$I= 12\;A$
n$= 30\%$
Input power = VI
$\qquad= 50 \times 12 =600 walt$
Since $n=30\%$ , the energy dissipated as heat
$P= \large\frac{70}{100}$
$\quad= \large\frac{70}{100} $$ \times 600$
$\qquad= 420\;w$
$P= I^2 R$
$R= \large\frac{P}{I^2}$
$\quad= \large\frac{420}{12 \times 12}$
$\quad= 2.9 \Omega$
or $ 3\;\Omega$ (approx)
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.
Continue
Please choose your payment mode to continue
Home Ask Homework Questions
Your payment for is successful.
Continue
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.
...