Question

21. The power cord used for charging your phone requires 22 W of power. If you are Europe, where the outlet voltage is 220 V, what would be the current required in the primary (in the outlet part of the power cord) a. 120 A b. 2200 A c. 22 A d. 10 A e. 0.1A 22. If you fill a plastic bottle halfway with hot tea, seal it, and place it in the refrigerator then you will find that the walls of the bottle collapse inwards. Which of the following is the best description of why? a. because the cooling tea in the bottle shrinks in volume b. because the cooling air in the bottle drops in pressure. C. because the cooling tea sucks molecules out of the air inside the bottle. d. because the pressure from the air in the refrigerator goes up because it is colder, e. because cold tea has an attractive force on plastic. 1. A 200-g wooden block is lowered carefully into a completely full beaker of water where it floats halfway submerged. What is the weight of the water that spills out of the beaker a. 0.1N b. 2N c. 40 N d. 200 N e. 1000 N mo

Answer 1

21.)

P = 22w

V = 220v

I = P/V = 22/220 = 0.1A

22.) Bottle will shrink inward because the air in bottle will reduce the pressure inside the bottle by decreasing volume.

23.) Weight of water displaced = weight of block submerged

Hence w = mg = 0.2×10 = 2N