Page 1 Rec 5 Worksheet — Current, Resistance and Ohm’s Law (an thingy Vilup Ex 1: A 12 V battery is connected across a device with variable resistance. As the resistance of the device increases, determine whether the following quantities increase, decrease, or remain unchanged. a) Th current through the device: Increase /|decrease P remains the same b) The voltage across the device: Increase / decrease /remains the same ¢) The power consumed by the device: Increase // remains the same V P = av~—am AV = | R=— Incfites B- v/ 1 Atnary iy J RETANT, Ex 2: A voltage AV is applied across the ends of a Nichrome heater wire having a cross-sectional area A and length L. The same voltage is applied across the ends of a second Nichrome heater wire having a cross-sectional area A and length 2L. Which wire gets hotter? <™ Moj4 ¢yt nt [a) the shorterV\./ire | i e h wine L LLn b) the longer wire /| T ) N = 5L e ¢) more information is needed > | [ | I Ex 3: (a) A rectangular block has the dimensions L X w X h. e When a battery with a voltage AV is connected across the end Lw 4 NY faces as shown in the left figure above, a current I, flows through {/ L the circuit. ¢ AV o When the same battery is connected across the top and bottom Q" faces of the block as shown in Fig. b, a current I, flows through it. - Which current is larger? {-L = Wl 9.2 Current I, / Both currents are equal l R g 3 0 ] & i § o | % ,..__, n& L f\blgl\it b ‘L‘L;;J’fi I\ I/‘ Ex 4: Three light bulbs are connected in series as shown. They have different resistance. The dots in the figure are just some points we want to study. hidki el AN Nty Bill; pl R =10000 a) How do the current in different part of the circuit compare? Rank the current passing through points a, b, ¢,d, e, f and g. =l ol Largest current h= b = () (J = L= | = (| smallest current IZ‘E’L_ Sk [ _-— R= 109 g TR b) Suppose the circuit is broken at point e (as shown by an X). ‘ How do the current in different part of the circuit compare? Rank f e\ the current passing through points a, b, c, d,e, f and g. 20:;!;09 X beklt\( Largest current I = (\ 10X (I“ smallest current e AV X (mm(hd n Mg ¢o