Ohm's Law Objective Exam Questions - ObjectiveBooks

# Practice Test: Question Set - 03

1. A resistor is connected across a 50 V source. What is the current in the resistor if the color code is red, orange and silver?
(A) 2 mA
(B) 2.2 mA
(C) 214 mA
(D) 21.4 mA

2. How much resistance is required to limit the current from a 12 V battery to 3.6 mA?
(A) 3.3 kΩ
(B) 33 kΩ
(C) 2.2 kΩ
(D) 22 kΩ

3. What is the approximate resistance setting of a rheostat in which 650 mA of current flows with a 150 V source?
(A) 9.7 Ω
(B) 97 Ω
(C) 23 Ω
(D) 230 Ω

4. You are measuring the current in a circuit that is operated on an 18 V battery. The ammeter reads 40 mA. Later you notice the current has dropped to 20 mA. How much has the voltage changed?
(A) 9 V
(B) 900 mV
(C) 0 V
(D) 18 V

5. The current through a flashlight bulb is 40 mA and the total battery voltage is 4.5 V. The resistance of the bulb is approximately
(A) 112 Ω
(B) 11.2 Ω
(C) 1.2 Ω
(D) 18 Ω

6. A current of 200 µA through a 6.8 kΩ resistor produces a voltage drop of
(A) 34.4 V
(B) 340 V
(C) 13.6 V
(D) 1.36 V

7. According to Ohm’s Law
(A) V is directly proportional to I
(B) V is inversely proportional to I
(C) V is directly proportional to √I
(D) All o the above

8. Four amperes of current are measured through a 24 Ω resistor connected across a voltage source. How much voltage does the source produce?
(A) 960 V
(B) 9.6 V
(C) 96 V
(D) 8 V

9. Approximately how much current flows through a 3.3 MΩ resistor across a 30 V source?
(A) 9 μA
(B) 90 μA
(C) 900 μA
(D) 9000 μA

10. What is the approximate filament resistance of a light bulb if it operates from a 110 V source and 0.6 A of current is flowing?
(A) 183 Ω
(B) 18.3 Ω
(C) 66 Ω
(D) 6.6 Ω

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