An ammeter whose internal resistance is 60 $\Omega$ reads 5.25 mA when connected in a circuit containing a battery and two resistors in series whose values are $700 ~\Omega$ and $400 ~\Omega$. What is the actual current when the ammeter is absent?

A milliammeter reads 10 mA full scale. It consists of a 0.20-$\Omega$ resistor in parallel with a 30-$\Omega$ galvanometer. How can you change this ammeter to a voltmeter giving a full-scale reading of $10 ~\mathrm{V}$ without taking the ammeter apart? What will be the sensitivity $(\Omega/\mathrm{V})$ of your voltmeter?

Draw the Lewis structure for molecule C3H4 . How many sigma and pi bonds does it contain?

a. 8 sigma, 2 pi

b. 10 sigma, 2 pi

c. 6 sigma, 2 pi

d. 8 sigma, 0 pi

e. 7 sigma, 0 pi

A galvanometer has a sensitivity of 35 k$\Omega/\mathrm{V}$ and internal resistance 20.0 $\Omega$. How could you make this into (a) an ammeter that reads $2.0 ~\mathrm{A}$ full scale, or (b) a voltmeter reading $1.00 ~\mathrm{V}$ full scale?

A galvanometer has an internal resistance of 30 $\Omega$ and deflects full scale for a 50-$\mu$A current. Describe how to use this galvanometer to make (a) an ammeter to read currents up to $30 ~\mathrm{A}$, and (b) a voltmeter to give a full-scale deflection of $1000 ~\mathrm{V}$.

An ammeter has a sensitivity of 10,000 $\Omega/\mathrm{V}$. What current passing through the galvanometer produces full-scale deflection?

What is the resistance of a voltmeter on the 250-V scale if the meter sensitivity is 30,000 $\Omega/\mathrm{V}?$

The RC circuit of earlier Fig. has R = 6.7 k$\Omega$ and C = 3.0 $\mu$F. The capacitor is at voltage $V_o$ at t = 0, when the switch is closed. How long does it take the capacitor to discharge to $1.0$ percent of its initial voltage?

A charge 2q is at the origin, and a charge −q is at x=a on the x axis. (a) Find the point on the x axis where the electric field is zero. (b) Consider the vertical line passing through the charge −q, that is, the line given by x=a. Locate, at least approximately, a point on this line where the electric field is parallel to the x axis.

In earlier figure, the total resistance is 15 k$\Omega$ and the battery's emf is 24.0 V. If the time constant is measured to be 35 $\mu$s, calculate (a) the total capacitance of the circuit and (b) the time it takes for the voltage across the resistor to reach $16.0 ~\mathrm{V}$.

Suppose a 7.5-$\mu$F capacitor replaced the 10.0-$\Omega$ resistor in earlier Figure. Calculate: (a) the charge on the capacitor in the steady state-that is, after the capacitor reaches its maximum charge; (b) the steady state current through the other resistors.

At $0.095 per kWh, what does it cost to leave a 25-W porch light on day and night for a year?

Describe carefully the difference between emf and potential difference.

Suppose that you have a 6.0-V battery and you wish to apply a voltage of only 4.0 V. Given an unlimited supply of $1.0$-$\Omega$ resistors, how could you connect them so as to make a "voltage divider" that produced a $4.0$-$\mathrm{V}$ output for a $6.0$-$\mathrm{V}$ input?