Question

A 50-ω resistor is connected to a 9.0 V battery. How much thermal energy is produced in 7.5 minutes?1.2 * 10^2 J1.3 * 10^3 J3.0 * 10^2 J7.3 * 10^2 J

Answer 1

In order to calculate the thermal energy, first let's calculate the power, using the formula:

`P=(V^2)/(R)`

For a voltage V = 9 Volts and a resistance R = 50 ohms, we have:

`\begin{gathered} P=(9^2)/(50) \\ P=(81)/(50)=1.62\text{ W} \end{gathered}`

Now, multiplying the power by the time (in seconds), we can find the energy:

`\begin{gathered} E=P\cdot t \\ E=1.62\cdot7.5\cdot60 \\ E=729\text{ J} \end{gathered}`

In scientific notation, we have an energy of 7.3 * 10^2 J, therefore the correct option is the fourth one.