Question

20. If four identical lamps are connected in parallel and the combined resistance
is 100ohm, find the resistance of one lamp.

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Answer 1

$\huge{\textbf {\underline \underline{ANSWER}}}$



The identical lamps are connected in parallel.



Equivalent resistance = 100 ohms



Let each resistance be x ohms



so ..




$\frac{1}{x} + \frac{1}{x} + \frac{1}{x} + \frac{1}{x} = \frac{1}{100} \\ \\ \\ \frac{4}{x} = \frac{1}{100} \\ \\ \\ x = 400$




So the resistance of a lamp is 400 ohms .




thanks .

Answer 2

$\huge \bold{hey \: there}$

Let the resistance of each lamp be x ohms.

It is given that 4 identical lamps are connected in parallel, so

➡1/R=1/R1+1/R2+1/R3+1/R4

The combined resistance is 100 ohms,

Now,

➡1/100=1/x+1/x+1/x+1/x

➡1/100=4/x

➡1/100×4=1/x

➡1/400=1/x

➡x=400 ohms

Therefore, resitance of each lamp is 400 ohms.