Question

In physics, Ohm's law says that current through a wire, I, is directly proportional to voltage, V, and inversely proportional to resistance, R:I=V/RIt's also true that resistance is directly proportional to the length of the wire. We have a piece of wire. We pass 60 volts through this wire and measure 300 milliamps of current. If I cut the wire in half and pass 200 volts through it, how many milliamps of current will I measure?

Answer 1

2000 milliamps

Explanation:

According to Ohm's law, I = V/R, where I is the current through the wire, V is the voltage across the wire, and R is the resistance of the wire. We can use this formula to solve the problem.

Let's start by finding the resistance of the original wire. We are given that when 60 volts is passed through the wire, the current is 300 milliamps. So, we can write:

300 milliamps = 0.3 amps (since 1 amp = 1000 milliamps)

60 volts = V

R = V/I = 60/0.3 = 200 ohms

So, the resistance of the original wire is 200 ohms.

Now, let's consider the new wire that is obtained by cutting the original wire in half. Since resistance is directly proportional to the length of the wire, we know that the resistance of the new wire will be half of the resistance of the original wire. So, the resistance of the new wire is:

R_new = R/2 = 200/2 = 100 ohms

We are also given that when 200 volts is passed through the new wire, we want to find the current. Using Ohm's law, we can write:

I_new = V_new/R_new = 200/100 = 2 amps

However, the problem asks for the current in milliamps, so we need to convert our answer to milliamps:

I_new = 2 amps = 2000 milliamps

Therefore, if we cut the wire in half and pass 200 volts through it, we will measure a current of 2000 milliamps.

Answer 2

Explanation:

V = I R

V/R = I NOW Cut R in half

and multiply V x 3 1/3 ( because 60 volts x 3 1/3 = 200 v)

10/3 V / ( 1/2 R) = 20/3 V/R SO CURRENT WILL BE INCREASED 20/3 TIMES ORIGINAL 20/3 * 300 mA = 2000 mA = 2 amps