question from current electricity
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We have V = IR
Therefore, R = V/I = 6.5 / (2/3) = 6.5 * 2 /3 = 9.75 ohms
The total resistance of the circuit is 9.754 ohms.
The 5 ohm resistor and the resistor marked 'R' are in parallel. Thus, their resultant will be 5R/5+R ohms.
Now, we can see that this resultant resistance is in series with the 2 ohm and 4 ohm resistors.
Thus the effective resistance in the circuit is 2 + 4 + (5R/5+R) = 9.75
5R/5+R = 9.75 - 6 = 3.75
5R = 3.75(5+R)
5R-3.75R=18.75
1.25R=18.75
Thus R = 18.75/1.25 = 15 ohms
Hence (c) is the correct option.
Therefore, R = V/I = 6.5 / (2/3) = 6.5 * 2 /3 = 9.75 ohms
The total resistance of the circuit is 9.754 ohms.
The 5 ohm resistor and the resistor marked 'R' are in parallel. Thus, their resultant will be 5R/5+R ohms.
Now, we can see that this resultant resistance is in series with the 2 ohm and 4 ohm resistors.
Thus the effective resistance in the circuit is 2 + 4 + (5R/5+R) = 9.75
5R/5+R = 9.75 - 6 = 3.75
5R = 3.75(5+R)
5R-3.75R=18.75
1.25R=18.75
Thus R = 18.75/1.25 = 15 ohms
Hence (c) is the correct option.
Róunak:
Correct ans. ^_^
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