Why is the following situation impossible? A politician is decrying wasteful uses of energy and decides to focus on energy used to operate plug-in electric clocks in the United States. While many people use their smartphone as an alarm clock, he estimates that there are still 270 million plug-in alarm clocks in continuous use. The clocks transform energy taken in by electrical transmission at the average rate 2.50 W. The politician gives a speech in which he complains that, at today’s electrical rates, the nation is losing $100 million every year to operate these clocks.

What is the current (in Amps) in the circuit at t = 0.00500s?

15V a. + AM 10.2. 4 t=0 um 45² 652 im + V 1 ic (t) b. Assume switch has been closed for Find a mathematical expression for Vc it capacitor is initially uncharged and the switch is closed at t = 0. Sketch Vc lt). 20m F a long time. opening Fird an expression for ic immediately after the switch and sketch it.

There is a current of 0.25 A in the circuit of Figure P23.69.a. What is the direction of the current? Explain.b. What is the value of the resistance R?c. What is the power dissipated by R?d. Make a graph of potential versus position, starting from V = 0 V in the lower left corner and proceeding clockwise.See Figure P23.9 for an example.

V5

A physics student has a single-occupancy dorm room. The student has a small refrigerator that runs with a current 4 A, a lamp that contains a 100-W bulb, an overhead light with a 60-W bulb, and various other small devices adding up to 8 w. All the appliances run on a voltage of 110 V. Overall Hint a. What is the total power used by the dorm room (while the refrigerator runs)? Total power used by the dorm room is W. b. Assuming that the power plant for the electricity is 10 km away and uses 00-gauge copper wire (diameter 9.266 mm), how much power is dissipated in transmission (remember to count the return wire), if the power plant is directly providing the 110-V? (To be more precise, the power plant is providing the voltage it needs to provide, so that the voltage at the dorm room is 110 V.) Hint for part (b) Power of W is dissipated in transmission at 110 V. c. The most common way to increase the efficiency of power transmission is by using higher voltage for long-distance transmission…

A student reaches to open a door and gets a small electric shock. She knows that the shock is caused by static electricity, but it seems like in the winter she gets shocked more than in the summer. The student asks her science teacher if there are times of the year when there is more static electricity that builds up than other times of the year. The teacher replies that there is, and it depends on the humidity, or moisture in the air. The more humid the air is, the less static will build up and, therefore, the less you get shocked.   Explain why static electricity does not build up as much when the air is humid. In your response, be sure to include: an explanation of static electricity is formed. an explanation of why the student felt a shock when reaching for the door handle. an explanation of how moisture in the air allows static electricity to dissipate.   Be sure to consider the completeness of your response, supporting details, and accurate use of terms.

When the switch is in position a below,  the battery charges the positive parallel plate of the capacitor to Q = 900 µC.  The switch then swings to position b,  the charge Q  flows through the resistor R, and the capacitor’s stored energy U is turned into heat energy.  Assume the capacitor has capacitance C = 8.00 µF. Use conservation of energy to find the amount of heat (in Joules) produced during the capacitor’s discharge.

A student in the laboratory connects a 17 Ω resistor, a 26 Ω resistor, and a 34 Ω resistor in parallel and then connects the arrangement to a 46 V dc source. (a) What is the current? A(b) What is the power? W