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Ron P, , + EXERCISES +, , . Very-Short-Answer Questions, , Write the unit of electric potential., , . Define the potential at a point., . Define the potential difference between two points., . A dry cell usually has a small cap at one end and a, , flat surface at the other end. Which of the two is at a, higher potential?, , . Name the instruments used to measure electric, , current and potential difference respectively. Which, of these is connected in series and which is, connected in parallel in a circuit?, , . What is the shape of the graph between V and i,, , where V is the potential difference between the ends, of a wire and j is the current in it?, , . Consider the units volt, ohm and ampere. One of, , them is the same as the product of the other two., Which one is this?, , . Name three electrical appliances in which the, , heating effect of electric current is used., , . Two bulbs have ratings 100 W, 220 V and 60 W,, , 220 V. Which one has a greater resistance?, , . You have two resistors of resistances 30 2 and 60., , What resistances can you get by combining the two?, , . Draw a diagram to show two resistors R, and R,, , connected in series, (2006), , . Two resistors of 502 and 10M are connected in series, , in a circuit. How does the current passing through, them compare? (2006), , 13., , A wire of resistance 10 Q is bent to form a closed, circle, What is the resistance across a diameter of, the circle? (2005), , . Short-Answer Questions, - What is the difference between a conductor and an, , insulator? Give one example of each., , . The current in a wire is one ampere. Explain this, , Statement in terms of the charge flowing through, the wire., , . When do you say that the resistance of a wire is 19?, . Draw a circuit diagram for a circuit in which two, , resistors A and B are joined in series with a battery,, and a voltmeter is connected to measure the, potential difference across the resistor A., , When are resistors said to be connected in series?, , . When are resistors said to be connected in parallel?, Why is tungsten suitable for making the filament of, , a bulb?, , . Why is tungsten not used as a fuse wire?, . Alloys are preferred over metals for making the, , heating element of heaters. Why?, , . Silver isa better conductor of electricity than copper., , Why then do we use copper wire for conducting, electricity?, , . Long-Answer Questions, . State Ohm's law. How can it be verified?, . When the terminals of a cell are connected to the, , ends of an iron rod, electric current flows through