Electricity and Magnetism Practice

_______ are the charged parts of an atom.

• Only Electrons

• Only Protons

• Protons and Electrons

• Protrons and Neutrons

Answer explanation

Electrons are negatively charged and protons are positively charged. The neutrons do not have a charge.

Someone says, "A positively charged object is an object that has an excess of positive electrons." How should we respond?

• Yeee that's correct!

• Bruh. No. Excess electrons = negative.

• 10 electrons

Answer explanation

Given:

-10 C charge

1 electron per -1.6 x 10^-19 C

Calculation:

-10 C/(-1.6 x 10^-19) C

= 6.25 x 10 ^19

A positive charge moving with a constant velocity v enters a region of a uniform magnetic field pointing into the page. What is the direction of the magnetic force on the charge?

• Left

• Right

• Clockwise

• Counter-clockwise

Answer explanation

Magnetic Field: Point fingers into the page

+ Charge: Point thumb upward

Force: Direction your palm faces (left)

2 Amps of current flows through a 0.50 m wire. Calculate the force acting on the wire when it is placed at right angles in a 0.4 Tesla magnetic field.

• F = 0.4 Newtons

• F = 1.4 Newtons

• F = 0.2 Newtons

• F = 1.4 Newtons

• F = 2.25 Newtons

• F = 0.225 Newtons

• F = 0.0225 Newtons

• F = 0.000225 Newtons

What instrument is used to measure electric current?

• Voltmeter

• Ammeter

What is the unit of electric current?

• Coulomb (C)

• Volts (V)

• Amps (A)

• Watts (W)

What is the unit of electrical resistance?

• Coulomb (C)

• Amps (A)

• Watts (W)

A current of 0.5 A flows through a 22 Ω resistor. What is the value of the voltage across it?

• .23 V

• 11 V

• 44 V

• 1.62 V