9. Work & Energy

Which of the following best describes a power transmission device in physics?

Which unit is most commonly used to measure electrical power?

If a laser emits a single pulse delivering energy $E$ over a time interval $t$, what is the power of one laser pulse?

A $1500$-$W$ heater is connected to a $120$-$V$ line for $2.0$ $\mathrm{hours}$. How much heat energy, in $\mathrm{joules}$, is produced by the heater during this time?

If a $1500$−W heater is designed to be plugged into a $120$−V outlet, what is the current drawn by the heater?

A $100$ watt light bulb operates for $1$ hour. How many $J$ (joules) of energy does it consume during that time?

Four students, each with a mass of $m$, run up a flight of stairs of height $h$. The times taken are: Student A: $4$ s, Student B: $6$ s, Student C: $5$ s, Student D: $8$ s. Which student has the largest power output?

Which of the following is the SI unit of power?

Which of the following is not a unit of power?

To which of the following is the $W$ (watt) equal?

A circuit contains a $12\Omega$ resistor with a current of $2A$ flowing through it. How much power is dissipated by the resistor?

Astronomers using a 2.0-m-diameter telescope observe a distant supernova - an exploding star. The telescope's detector records 9.1 x 10^-11 J of light energy during the first 10 s. It's known that this type of supernova has a visible-light power output of 5.0 x 10³⁷ W for the first 10 s of the explosion. How distant is the supernova? Give your answer in light years, where one light year is the distance light travels in one year. The speed of light is 3.0 x 10⁸ m/s.

Which physical quantity is measured in watts ($W$)?

$What\; is\; the\; SI\; unit\; for\; power?$

Power is measured in which unit?