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Attempts 127

If an electric oven has a resistance of 40 Ω when heating, what will be the current flowing through it when it’s connected to a110 V power line?

  1. A
    0.36 A
  2. B
    2.75 A
  3. C
    3.64 A
  4. D
    4.40 kA

Topic Flashcards

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Question

State Ohm's Law as a formula and identify the standard unit for each variable.

Answer

I = V R I= R V ​ , where I I is current in amperes (A), V V is voltage in volts (V), and R R is resistance in ohms (Ω).

Question

A coffee maker has a resistance of 22 Ω. What current does it draw when connected to a standard 110 V household outlet?

Answer

I=V/R=110V/22Ω=5.0A.

Question

If a hair dryer draws 9.17 A from a 110 V circuit, what is its operating resistance?

Answer

R= I/ V ​ = 9.17A/110V ​ ≈12Ω.

Question

How does the current through a fixed-resistance appliance change if the supply voltage is reduced by half?

Answer

The current is also halved, since I ∝ V I∝V when R R is constant ( I = V R I= V/R ​ ).

Question

An electric heater draws 2.75 A at 110 V. Calculate the power it dissipates in watts.

Answer

A: P = V × I = 110   V × 2.75   A = 302.5   W P=V×I=110V×2.75A=302.5W. (Alternatively, P = I 2 R P=I 2 R

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Does Ohm's Law apply to all materials and electronic components under all conditions?
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