BSc Systems 2 Extra Assignment 2008 Submit by 5 th May 2008 Paul Flynn

Transcription

1 1.) If a current of 3 is divided by the following circuit, the current flowing through the 4 Ohm resistor is , ) The diagram at the right shows part of a circuit into which a current I is flowing. Which ammeter shows the highest reading? ll three ammeters 4 give the same reading 3.) The diagram to the right represents a part of a circuit containing an ohmic resistor, a voltmeter and an ammeter. If the reading on the ammeter increases the reading on voltmeter V 1 increases in the same ratio. increases, but not in the 2 same ratio. 3 remains unchanged. 4 decreases in the same ratio. 1

2 4.) battery is connected to two identical light bulbs in parallel as well as another identical bulb in series. n ammeter and a voltmeter are also connected as shown in the circuit diagram below. One of the light bulbs connected in parallel is unscrewed. How will the ammeter and the voltmeter readings change? Voltmeter reading mmeter reading 1 increases increases 2 increases decreases 3 increases unchanged 4 decreases decreases 5.) learner connects a circuit as shown in the diagram to the right. He/she uses a source of electricity with an electromotive force (emf) of 12 V. Which one of the following best gives the ammeter and voltmeter readings which the learner is most likely to get with this circuit? mmeter reading Voltmeter reading 1 reads zero reads zero 2 reads zero reads 12 V 3 very large reading reads zero 4 very large reading reads 12 V 2

3 6.) Three identical resistors of 4 Ω are connected to give a combined resistance of 6 Ω. Which of the following circuit diagrams illustrates how this was done? 1 I 2 II 3 III 4 IV 7.) In the circuit to the right B 1, B 2 and B 3 are identical light bulbs. The internal resistance of the battery can be ignored. Which statement is true regarding the relative brightness of the bulbs? The three bulbs glo 1 with the same brightness. B 2 and B 3 glow wi 2 the same brightnes but brighter than B B 2 and B 3 glow wi the same brightnes 3 but less brightly th B 1. B 1 glows brighter than B 2 while B 2 in 4 turn glows brighte than B 3. 3

4 8.) Two identical light bulbs, X and Y, are connected in series as shown in the sketch to the right. How will the brightness of the bulbs change if switch S is closed? X Y 1 brighter brighter 2 dimmer dimmer 3 brighter not lit up 4 not lit up brighter 9.) student connects three identical resistors as shown in the sketch to the right. The potential difference across the battery is 12 Volt. What are the readings on V 1 and V 2 respectively? V 1 V ) 9 V battery is composed of six 1,5 V cells, which are connected in series. Each cell has an internal resistance of 0,2 Ω. What is the highest current that can be obtained from such a battery? 1 7,5 2 1,5 3 1,2 4 0,3 4

5 11.) onsider the electric circuit shown in the diagram at the right. The reading on the voltmeter V is... B 0 V 2 V 4 V 6 V 12.) Two light bulbs P and Q are identical in all respects, except that P's filament is thicker than Q's. If the same potential difference is applied to each, then B P will burn brighter because it has the greater resistance. Q will burn brighter because it has the greater resistance. P will burn brighter because it has the lower resistance. Q will burn brighter because it has the lower resistance. 13.) The ammeter and the battery in the sketch to the right have negligible resistance. The resistors are in parallel. What will happen to the ammeter and voltmeter readings when switch S is closed? ammeter reading voltmeter reading increases unchanged B increases increases decreases decreases decreases increases 5

6 14.) In the circuit shown the bulb marked 2R has twice the resistance of the bulb marked R. ompared with bulb 2R, the current in bulb R and its brightness compared to the other bulb, is current in R brightness in 2R larger brighter B larger dimmer smaller brighter smaller dimmer 15.) Mary has connected four identical light bulbs in a circuit as shown to the right. She observes that the brightness of bulb varies if some of the switches are closed. In which case will bulb burn brightest? B S 1 closed with S 2 and S 3 open S 1 and S 2 closed with S 3 open S 1, S 2 and S 3 closed S 1, S 2 and S 3 open 16.) Two identical light bulbs X and Y, which are rated at 60 W; 240 V, are connected in series to a 240 V source as shown in the diagram below. If point in the circuit is now connected to point B by a piece of copper wire with very low resistance, how will the brightness of each bulb change? 6

7 B Both X and Y will burn brighter. Both X and Y will burn less brightly. X will burn brighter and Y will not burn. Y will burn brighter and X will not burn. 17.) battery is connected to a small lamp. If a second identical lamp is connected in series with the first, what will happen to the current provided by the battery? it will decrease B it will remain the same it will increase it will become zero 18.) 200 V electrical outlet is protected by a circuit breaker. The circuit breaker will cut out if the current drawn from the outlets exceeds W toaster and a 2000 W kettle can be connected to the outlet, either singly, or both in parallel using a double adapter. Which use of the appliances will trip the circuit breaker? the toaster used on its own B the kettle used on its own the toaster and the kettle together none of the above 7

8 19.) Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then the resistance of the second is ¼ R B ½ R 2 R 4 R 20.) 10. Two resistors of resistance 2R and 3R are connected in series with a battery, which has an emf of E and an internal resistance R. What is the potential difference across the resistor of resistance 2R? E/3 B 2E/5 E/2 2E 8