Reviewestions 34. The graph below shows the relationship 29. A total of 20.0 coulombs of charge pass a given between potential difference and current in a point in a conductor in 4.0 seconds. Calculate simple circuit. [Assume constant temperature.) the current in the conductor. 30. A wire carries a current of 2.0 amperes. How many electrons pass a given point in this wire in difference Potential 1.0 second? (3) 1.3 x 1019 (1) 1.3 X 10 4) 20 X 1019 2) 2.0 X 1018 31. Which condition must exist between two points Current in a conductor in order to maintain a flow of charge? For any point on the line, what does the ratio of (1) a potential difference potential difference to current represent? (2) a magnetic field (1) resistivity in ohm meters (3) a low resistance (2) power in watts (4) a high resistance (3) resistance in ohms 32. A simple circuit consists of a variable resistor (4) charge in coulombs connected to a battery. An ammeter and a voltmeter are connected properly in the circuit 35. A 20.-ohm resistor has 40. coulombs of charge to measure the current through and potential passing through it in 5.0 seconds. Calculate the drop across the variable resistor. What is the potential difference across the resistor. effect of increasing the resistance of the variable 36. The graph below represents the relationship resistor from 10* ohms to 10* ohms ? [Assume between the potential difference across a constant temperature.] metal conductor and the current through the (1) The ammeter reading decreases. conductor at constant temperature. 2) The ammeter reading increases. Potential Difference (3) The voltmeter reading decreases. vs. Current (4) The voltmeter reading increases. 8.0 33. An electric circuit contains a variable resistor 6.0 connected to a source of constant potential Potential difference (V) difference. Which graph best represents the 4.0 relationship between current and resistance in 2.0 this circuit? 0 0.2 0.4 0.6 0.8 Current (A) Current Current What is the resistance of the conductor? ns. Resistance Resistance (1) (2) Current Current Resistance Resistance (3) (4) 124 Topic 4: Electricity and Magnetism