A 50 volt battery is connected across a 10 ohm resistor. The current is 4.5 amp. The internal resistance of battery will be

Question

A 50 volt battery is connected across a 10 ohm resistor. The current is 4.5 amp. The internal resistance of battery will be (A)  5.0 Ω  (B)  1.1 Ω  (C)  0.5 Ω  (D) zero

Tardigrade Admin · Accepted Answer

Using the relation i=(E/R +r) (given: E=50 V, R=10 Ω i=4.5 amp 4.5=(50/10+r) 45+4.5 r=50 4.5 r=50-45=5 or r=(5/4.5)=(10/9)=1.1 Ω

Q. A $50$ volt battery is connected across a $10$ ohm resistor. The current is $4.5$ amp. The internal resistance of battery will be

$5.0 Ω$

$1.1 Ω$

$0.5 Ω$

zero

Using the relation
$i = \frac{E}{R + r}$
(given : $E = 50 V, R = 10 Ω i = 4.5 am p}$
$4.5 = \frac{50}{10 + r}$
$45 + 4.5 r = 50$
$4.5 r = 50 - 45 = 5$
or $r = \frac{5}{4.5} = \frac{10}{9} = 1.1 Ω$

Q. A 50 volt battery is connected across a 10 ohm resistor. The current is 4.5 amp. The internal resistance of battery will be

5.0Ω

1.1Ω

0.5Ω