A 2.2 kilo ohm resistor in a stereo system dissipates 42mW of power. What is the voltage across the resistor?

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When current is passed through a resistor there is a dissipation of power. The power dissipated if a current I is passed through a resistor with resistance R is I^2*R

In the problem the resistance of the stereo system is given as 2.2*10^3 ohm and the power dissipated is 42...

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When current is passed through a resistor there is a dissipation of power. The power dissipated if a current I is passed through a resistor with resistance R is I^2*R

In the problem the resistance of the stereo system is given as 2.2*10^3 ohm and the power dissipated is 42 mW.

=> I^2*(2.2*10^3) = 42*10^-3

=> I = sqrt(42*10^-3/(2.2*10^3))

=> I = sqrt(1.909*10^-5)

=> I = 4.36*10^-3

The voltage across a resistor R that makes a current I pass through it is given by V = I*R

This gives the voltage across the resistor as 4.36*10^-3*2.2*10^3 = 9.6 V

The voltage across the resistor is 9.6 V

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