24. Electric Force & Field; Gauss' Law

In an electric motor, what is the primary role of $\mathrm{electric charge}$?

Which of the following is the main disadvantage of parallel circuits?

Suppose three point charges are arranged at the vertices of an equilateral triangle. If each charge has magnitude $q$ and the side length of the triangle is $a$, what is the magnitude of the net electric force on one of the charges due to the other two?

A circuit contains a resistor and a capacitor in series with a battery. At time $t=0$ s, the current is $i_0$. At what time in $\mu s$ will the current decrease to $\frac{1}{2}{i}_0$?

When a cathode ray is deflected by a magnetic field, what can you conclude about the nature of the particles in the ray?

A circuit has a peak voltage of $310V$. What is the average (mean) value of the voltage for a full cycle of a sinusoidal AC waveform?

How does wetness affect the electrical resistance of the human body?

Which of the following best describes a closed loop of conductors through which electric charges flow?

Which of the following is an important step in how an electric motor uses $B$ (magnetic field) force to produce motion?

Two small spheres, each of mass $m$ and carrying equal charges $q$, are suspended from a common point by two insulating threads of length $L$. The spheres are in equilibrium and the threads make an angle $\theta$ with the vertical. What is the magnitude of the electric force on one of the masses?

Two pairs of point charges are shown. Pair A consists of charges $q$ and $q$ separated by distance $r$. Pair B consists of charges $q$ and $-q$ separated by the same distance $r$. Which pair experiences an attractive force between the charges?

Which statement best describes the difference between an open circuit and a closed circuit in terms of electric charge flow?

When is static electricity most noticeable and why?

Two point charges, $q_a$ and $q_b$, are separated by a distance $r$. What is the magnitude of the net electric force on charge $q_a$ due to charge $q_b$?

How does the electric current produced by an $AC$ generator differ from that produced by a $DC$ generator?