 # Concept Questions with Answers 8.02 W10D2

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Concept Questions with Answers 8.02 W10D2

Week 04, Day 2 W10D2 DC Circuits Today’s Reading Assignment W10D2 DC Circuits & Kirchhoff’s Loop Rules Course Notes: Sections 2 Class 09 2

Concept Q: Resistors In Parallel
Suppose that Then the equivalent resistance 2. 3. 4. Class 12

Concept Q: Resistors In Parallel
Answer. When Then the equivalent resistance is the smaller resistance. This is an important circuit design principle. Class 12

Concept Question: Bulbs & Batteries
An ideal battery is hooked to a light bulb with wires. A second identical light bulb is connected in parallel to the first light bulb. After the second light bulb is connected, the current from the battery compared to when only one bulb was connected. Is Higher Is Lower Is The Same Don’t know Class 12

Concept Question Answer: Bulbs & Batteries
Answer: 1. More current flows from the battery There are several ways to see this: (A) The equivalent resistance of the two light bulbs in parallel is half that of one of the bulbs, and since the resistance is lower the current is higher, for a given voltage. (B) The battery must keep two resistances at the same potential  I doubles. Class 12

Concept Question: Bulbs & Batteries
An ideal battery is hooked to a light bulb with wires. A second identical light bulb is connected in series with the first light bulb. After the second light bulb is connected, the current from the battery compared to when only one bulb was connected. Is Higher Is Lower Is The Same Class 12

Concept Question Answer: Bulbs & Batteries
Answer: 2. Less current flows from the battery The equivalent resistance of the two light bulbs in series is twice that of one of the bulbs, and since the resistance is higher the current is lower, for the given voltage. Class 12

Concept Question: Power
An ideal battery is hooked to a light bulb with wires. A second identical light bulb is connected in parallel to the first light bulb. After the second light bulb is connected, the power output from the battery (compared to when only one bulb was connected) Is four times higher Is twice as high Is the same Is half as much Is ¼ as much Class 14

Answer: 2. Is twice as high The current from the battery must double (it must raise two light bulbs to the same voltage difference) and Class 14

Concept Question: Power
An ideal battery is hooked to a light bulb with wires. A second identical light bulb is connected in series with the first light bulb. After the second light bulb is connected, the light (power) from the first bulb (compared to when only one bulb was connected) Is four times higher Is twice as high Is the same Is half as much Is ¼ as much Class 14

Answer: 5. Is 1/4 as bright R doubles  current is cut in half. So power delivered by the battery is half what it was. But that power is further divided between two bulbs now. Class 14

Concept Question: Measuring Current
If R1 > R2, compare the currents measured by the three ammeters: A1 > A2 > A3 A2 > A1 > A3 A3 > A1 > A2 A3 > A2 > A1 A3 > A1 = A2 None of the above Not enough information is given. Class 14