Tùng Science Final 1

Question: An battery is used to ________________. 1. maintain a potential difference 2. measure electric current 3. measure electric potential 4. safeguard against short - circuit

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Question: The unit of current is _____________. 1. ampere 2. watt 3. volt 4. coulomb

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Question: Three resistors 2 W , 3 W and 4 W are connected so that the equivalent resistance is 9 W . The resistors are connected _________. 1. all in series 2. all in parallel 3. 2 W and 3 W in parallel and the combination in series with 4 W 4. 2 W and 3 W in series and the combination in parallel to 4 W

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Question: Two resistances of 100 W and zero ohm are connected in parallel. The overall resistance will be 1. 100 W 2. 50 W 3. 25 W 4. zero ohm

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Question: When there is an electric current passing through a wire, the particles moving are _____________. 1. electrons 2. protons 3. atoms 4. ions

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Question: Four cells each of e.m.f 'E' are joined in parallel to form a battery. The equivalent e.m.f of the battery will be _______. 1. 4 E 2. E 3. E / 4 4. E = 0

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Question: Heat produced in a current carrying wire in 5s is 60 J. The same current is passed through another wire of half the resistance. The heat produced in 5 s will be _____________. 1. 60 J 2. 30 J 3. 15 J 4. 120 J

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Question: Joule / Coulomb is same as ______________. 1. watt 2. volt 3. ampere 4. ohm

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Question: The potential at a point is 20 V. The work done to bring a charge of 0.5 C from infinity to this point will be ________. 1. 20 J 2. 10 J 3. 5 J 4. 40 J

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Question: The potential difference required to pass a current 0.2 A in a wire of resistance 20W is ____. 1. 100 V 2. 4 V 3. .01 V 4. 40 V

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Question: The resistance of an electric bulb drawing 1.2 A current at 6.0 V is ___________. 1. 0 .5 W 2. 5 W 3. 0.2 W 4. 2 W

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Question: The work done in moving a unit positive charge across two points in an electric circuit is a measure of ___________. 1. current 2. potential difference 3. resistance 4. power

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Question: Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them are in the ratio _________. 1. 1:2 2. 2:1 3. 4:1 4. 1:1

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Question: When a current 'I' flows through a resistance 'R' for time 't' the electrical energy spent is given by ___________. 1. I R t 2. I2 R t 3. I R2 t 4. I 2 R / t

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Question: Kilowatt - hour is the unit of ______________. 1. potential difference 2. electric power 3. electrical energy 4. charge

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Question: Ohm's law relates potential difference with ___________. 1. power 2. energy 3. current 4. time

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Question: The current in a wire ______________. 1. depends only on the potential difference applied 2. depends only on the resistance of the wire 3. depends on both resistance and potential difference 4. does not depend on resistance and potential difference

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Question: The unit of resistivity is ____________. 1. ohm 2. ohm / m 3. ohm-m 4. mho

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Question: Which of the following is an ohmic resistor? 1. Diode 2. Germanium 3. Nichrome 4. Diamond

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Question: For which of the following substances, resistance decreases with temperature? 1. Copper 2. Platinum 3. Mercury 4. Carbon

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Question: The device used for measuring potential difference is known as _____________. 1. potentiometer 2. ammeter 3. galvanometer 4. voltmeter

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Question: The free electrons of a metal _____________. 1. do not collide with each other 2. are free to escape through the surface 3. are free to fall into the nuclei 4. are free to move anywhere in the metal

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Question: The path of a free electron in a metal is ___________. 1. parabolic 2. circular 3. a straight line 4. zig zag

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Question: The resistivity of a wire depends on ____. 1. length 2. material 3. area of cross- section 4. length, material and area of cross- section

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Question: Three equal resistances when combined in series are equivalent to 90 W . Their equivalent resistance when combined in parallel will be __________. 1. 270 W 2. 30 W 3. 810 W 4. 10 W

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Question: When a fuse is rated 8 A, it means _____________. 1. it will not work if current is less than 8 A 2. it has a resistance of 8 W 3. it will work only if current is 8 A 4. it will melt if current exceeds 8 A

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Question: Which of the following statements does not represent ohm's law? 1. current / potential difference = constant 2. potential difference / current = constant 3. potential difference = current x resistance 4. current = resistance x potential difference

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