Question

Which of the following would decrease current flow in a circuit made originally from a 6-volt battery, a loop of wire, and a switch?
Select one:
a. Using thicker wire
b. Opening the switch
c. Replacing the 6-V battery with a 12-V battery
d. None of these would decrease the current flow.

Answer 1

For a given closed circuit the current voltage and resistance of circuit is related with ohm's law

$V = i*R$

here

V = voltage difference due to battery

i = current flow in the circuit

R = resistance

so from above equation

$i = \frac{V}{R}$

so in order to decrease the current in the circuit we can either increase the resistance of the circuit or decrease the voltage

Now the formula of resistance is

$R =\rho \frac{L}{A}$

here

$\rho$ = resistivity of material of resistance

$L = resistance$

A = crossectional area

a) if we use a thick wire the as per above formula of resistance the value of resistance will decrease.

And hence the current will increase in the circuit so it is not correct option

b) If 6V battery is replaced by 12 V battery then due to increase in potential difference the current in the circuit will also increase, so this is not correct answer.

c)Opening the switch will decrease the voltage from 6 V to 0 Volt

due to this decrease in potential difference the current in the circuit will also decrease. So by Opening the switch the current will be decreased in this circuit.