# Potential Difference, Current and Resistance

1. In a particular television tube, the beam current is 60.0 MuA. How long does it take for 3.75 x 10^14 electrons to strike the screen?

2. A stereo with a resistance of 65 ohms is connected across a potential difference of 120 V. What is the current in this device?

3. The current in a microwave oven is 6.25 A. If the resistance of the oven's circuitry is 17.6 ohms, what is the potential difference across the oven?

Â© BrainMass Inc. brainmass.com October 6, 2022, 12:46 pm ad1c9bdddfhttps://brainmass.com/physics/resistance/potential-difference-current-resistance-16620

## SOLUTION This solution is **FREE** courtesy of BrainMass!

1. In a particular television tube, the beam current is 60.0 Mu A How long does it take for 3.75 x 10^14 electrons to strike the screen?

Current= 60 Mu A =60x10^(-6) A

1A=1Coulomb/Second

A current of 60 Mu A involves the transfer of charge of 60x10^(-6) Coulombs per second= 0.00006 Coulombs/sec

1 electron carries a charge of 1.6 x 10^-19 Coulombs

3.75 x 10^14 electrons will carry a charge of 0.00006 Coulombs =(3.75*10^14)*(1.6*10^-19)

This is equivalnet to a beam current of 60Mu A for 1 second

Thus if the beam current is of magnitude 60 Mu A it will take 1 second for 3.75 x 10^14 electrons to strike the screen

Answer: 1 second

2. A stereo with a resistance of 65 ohms is connected across a potential difference of 120 V. What is the current in this device?

Resistance= R= 65 ohms

Potential difference=V= 120 V

V=IR

or I=V/R= 1.85 Amperes (A) =120/65

Answer: 1.85 A

3. The current in a microwave oven is 6.25 A. If the resistance of the oven's circuitry is 17.6 ohms. What is the potential difference across the oven?

Resistance= R= 17.6 ohms

Current I= 6.25 A

Potential difference=V=IR= 110 V =17.6*6.25

Answer: 110 V

Â© BrainMass Inc. brainmass.com October 6, 2022, 12:46 pm ad1c9bdddf>https://brainmass.com/physics/resistance/potential-difference-current-resistance-16620