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If a current of 5 A flows through a resistor of 10 ohms for 2 minutes, the heat produced is:
500 J
15000 J
30000 J
50 J
30000 J
The heat produced in a resistor when current flows through it is governed by Joule's Law of Heating. Given the current I=5┬аA, resistance R=10┬а╬й, and time t=2┬аminutes, the heat H is calculated as H=I2Rt.
The heat produced in a resistor when current flows through it is governed by Joule's Law of Heating. Given the current I=5┬аA, resistance R=10┬а╬й, and time t=2┬аminutes, the heat H is calculated as H=I2Rt.
Think of a toaster wire glowing red; the electricity pushing through the high-resistance wire generates heat, similar to how rubbing your palms together creates heat due to friction.
HIRT (Heat = I Square R T)
H=I2Rt тАФ Joule's Law of heating where I is current, R is resistance, and t is time
t=2├Ч60=120┬аs тАФ Time conversion from minutes to seconds
Joule's Law of Heating states that the heat produced (H) in a conductor is directly proportional to the square of the current (I2), the resistance (R), and the time (t) for which the current flows. When electrons move through a conductor, they collide with atoms, transferring kinetic energy into thermal energy. In this problem, we must convert time to SI units: t=2├Ч60┬аs=120┬аs. Substituting the values, we get H=(5)2├Ч10├Ч120=25├Ч1200=30000┬аJ.
Always convert time to seconds (SI unit) before calculating heat in Joules.
Heat is directly proportional to the square of the current, meaning doubling the current quadruples the heat.
The resistance of a material determines how effectively it converts electrical energy into heat.
Used in heating appliances like electric iron, geysers, and fuses.
Leads to energy loss in transmission lines and reduces the efficiency of electrical devices.
Electric heaters and stoves
Incandescent light bulbs
The unit of heat produced is Joules (J), equivalent to Watts-seconds.
Option A (500 J) ignores the square of current and time conversion. Option B (15000 J) ignores the square of current.
C is correct тАФ Applying Joule's Law H=I2Rt with I=5┬аA, R=10┬а╬й, and t=120┬аs yields 30000┬аJ.
In physics problems, always verify that your units are consistent (A, Ohms, seconds) before substituting into equations to avoid common calculation errors.