Question

http://prntscr.com/8ie2s0

Answer 1

that looks like Chinese to me.

Answer 2

Okay.I'll type the question.

Answer 3

Three resistors are connected in parallel.Draw a circuit including a switch and a battery . Derive the equivalent resistance of such a circuit.

Answer 4

@zzr0ck3r
You there?

Answer 5

nono I am saying I don't know the subject...

Answer 6

lol

Answer 7

@welshfella @Abhisar

Answer 8

Do you know anything about Ohm's law?

Answer 9

Yep.

Answer 10

Good, so lets's start. I'll leave part (a) for you.

Answer 11

Actually,I got part(b) also.

Answer 12

Stcuk at part(c)

Answer 13

Stuck*

Answer 14

Ok, current in the circuit can be calculated by using the formula,

\(\sf \boxed{\Large I=\frac{Emf}{r+R}}\)

Answer 15

r=internal resistance,
R=external resistance

Answer 16

Curent = 0.06A?

Answer 17

0.096*

Answer 18

Yes.

Answer 19

I've no idea how to go about the rest :(

Answer 20

Potential difference across each resistor:

You know the current flowing (I) now.
use V=IR for each resistor. E.g. across 20 ohms resistor voltage drop will be 0.096*20

Answer 21

0.96*2?

Answer 22

WHat?

Answer 23

1.92V?

Answer 24

p.d across 20 ohm resistor is 1.92?

Answer 25

YEs.

Answer 26

and the latter is 0.48?

Answer 27

i.e across the 5 ohm resistor.

Answer 28

Yes

Answer 29

and across the cell?

Answer 30

Ok, let's do the last one first...

When the current is flowing, then the potential difference between the terminals of the cell < EMF

and that potential drop V is given by,

V= (emf of the cell) - Current X internal resistance.

V= 2.5 - 0.096 X 1

Answer 31

Getting it?
This is the solution for last one....

Answer 32

wait what?

Answer 33

that should be the p.d across the cell...

Answer 34

Nuuu...I explained it wrong earlier....chuck that from ur mind..

Answer 35

Is it clear now???

Answer 36

OK!

Answer 37

so p.d across the cell is?

Answer 38

Recall what we did to find the pd across resistors???

We multiplied their individual resistances with current flowing..Right?

Answer 39

Yep.

Answer 40

Similarly, to find pd across the cell we will multiply the current with resistance of cell i.e. internal resistance...

Answer 41

Can you find it for me?/

Answer 42

You mean 2.5*1?

Answer 43

What's the current?

Answer 44

0.096*2.5 = p.d across the cell?

Answer 45

Nuu..Current X Internal resistance....

Answer 46

Current = ?
Internal resistance = ?

Answer 47

Ugh...idk...... :'(

Answer 48

Internal resistance = 1 ohm

Answer 49

Internal resistance is given in the question and we calculated the current in 1st part :O

Answer 50

I know...Zoned out xD

Answer 51

Current is 0.096A and Internal Resistance is 1 ohm

Answer 52

Voltage drop = current*internal resitance right?

Answer 53

resistance*

Answer 54

Yes

Answer 55

so 0.096 is the voltage drop?

Answer 56

\(\huge \checkmark\)

Voltage drop across the cell