1. Intro to Physics Units

A forward-bias voltage of $15.0$ mV produces a positive current of $9.25$ mA through a $p-n$ junction at $300$ K. What does the positive current become if the forward-bias voltage is reduced to $10.0$ mV?

In household wiring, copper wire with a diameter of $2.05\mathrm{mm}$ is often used. What is the cross-sectional area of such a wire in $\mathrm{mm}{2}^2$ (square millimeters)?

Which statement is accurate about $mass$ or $weight$?

Which statement best describes the $m$eter as a unit of measurement?

Which of the following best describes a $\text{light year}$ as used in astronomy?

What is the SI unit for potential difference?

Calculate the minimum beam energy in a proton-proton collider to initiate the $p+p\to p+p+{\eta }^0$ reaction. The rest energy of the ${\eta }^0$ is $547.3$ MeV (see Table $44.3$).

Which of the following is the SI unit of measurement for electrical current?

Which of the following best describes physical science?

A particle has rest mass $6.64\times {10}^{-27}$ kg and momentum $2.10\times {10}^{-18}$ kgm/s.

(a) What is the total energy (kinetic plus rest energy) of the particle?

(b) What is the kinetic energy of the particle?

(c) What is the ratio of the kinetic energy to the rest energy of the particle?

Which of the following is the correct SI unit for acceleration?

Why is physics considered to be the basic science?

The atomic mass of $14C$ is $14.003242$ u. Show that the ${\beta }^{-}$ decay of $14C$ is energetically possible, and calculate the energy released in the decay.

A powerboat is operating at night. Which of the following lights must be displayed according to standard navigation rules?

The earth's circumference is approximately 40.1 Mm (megameters). What is this circumference in kilometers?