A circuit has a resistance of 200Ω. The resistance of the circuit can be reduced to 120Ω when
a
A 300Ω resistor is connected to it in parallel
b
An 80Ω resistor is conneceted to it in series
c
A 150Ω resistor is connected to it in parallel
d
A 240Ω resistor is connected to it in series
Explanation
Correct Option
aVideo Explanation
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Discussions (9)
Chizzylee384
4 years ago
To reduce a resistance we connect another resistor in parrallel. 1/120=1/200+1/R
1/120-1/200=1/R
5-3/600=1/R
1/R=2/600
R=600/2
R=300.
Therefore we connect another resistance of 300Ω in parallel
myschoolsam
2 years ago
1/120 = 1/200 + 1/R
Collect like terms
1/120 - 1/200 = 1/R
Lowest common factor of [1/120 - 1/1200]
4/1200 = 1/R
Cross multiply
R= 1200/4
R= 300
