Good question. A is correct.
First of all, this is “MUST BE TRUE” question. The most important thing of this type of question is “NO NEW information accepted”. A correct answer MUST pass the “Fact test”.
There are only 2 types of correct answer:
(1) Paraphrase (re-write parts of the stimulus in other way but keep the same meaning)
(2) Combination (combine two or more parts of the stimulus to make an inference)
ANALYZE THE STIMULUS:
Fact #1: Inertia affects the flow of water pumped through a closed system of pipes
Fact #2: The pump is on, inertia causes the mass water takes time to reach full speed.
Fact #3: The pump is off, inertia causes the decrease in the water flow to be gradual.
Fact #4: The effects of inductance in electrical circuits are similar to the effects of inertia in water pipes.
ANALYZE EACH ANSWER:
A. The rate at which electrical current flows is affected by inductance
Correct. This is a combination of fact#1 and fact#4: flow of water is affected by inertia; inductance affects electrical flows in the similar way as inertia does ==> Flow of electrical current is affected by inductance.
B. The flow of electrical current in a circuit requires inertia
Wrong. “Flow of electrical current is affected by inductance, not inertia”; In addition, “require” differs from “affects” ==> out immediately
C. Inertia in the flow of water pumped by an electrically powered pump is caused by inductance in the pump's circuit
Wrong. No direct link between “inertia in the flow of water” and “inductance in pump’s circuit” ==> Out immediately.
D. Electrical engineers try to minimize the effects of inductance in electrical circuits
Wrong. Nothing about “engineers try to minimize the effect of inductance” ==> Out immediately.
E. When a water pump is switched off it continues to pump water for a second or two
Wrong. SHELL GAME. Fact #3 just says: inertia causes the decrease in the water flow to be gradual. Thus, E is wrong because:
(1) The stimulus does not mention how long a water pump continues to pump.
(2) You cannot infer “decrease in the water flow to be gradual” = 1 or 2 seconds. It may be 3 seconds, or even a minutes, who knows?
TAKEAWAY:
In "Must be true" question:
(1) No new info accepted.
(2) A correct answer MUST pass the fact test.
Hope it helps.
First of all, this is “MUST BE TRUE” question. The most important thing of this type of question is “NO NEW information accepted”. A correct answer MUST pass the “Fact test”.
There are only 2 types of correct answer:
(1) Paraphrase (re-write parts of the stimulus in other way but keep the same meaning)
(2) Combination (combine two or more parts of the stimulus to make an inference)
ANALYZE THE STIMULUS:
Fact #1: Inertia affects the flow of water pumped through a closed system of pipes
Fact #2: The pump is on, inertia causes the mass water takes time to reach full speed.
Fact #3: The pump is off, inertia causes the decrease in the water flow to be gradual.
Fact #4: The effects of inductance in electrical circuits are similar to the effects of inertia in water pipes.
ANALYZE EACH ANSWER:
A. The rate at which electrical current flows is affected by inductance
Correct. This is a combination of fact#1 and fact#4: flow of water is affected by inertia; inductance affects electrical flows in the similar way as inertia does ==> Flow of electrical current is affected by inductance.
B. The flow of electrical current in a circuit requires inertia
Wrong. “Flow of electrical current is affected by inductance, not inertia”; In addition, “require” differs from “affects” ==> out immediately
C. Inertia in the flow of water pumped by an electrically powered pump is caused by inductance in the pump's circuit
Wrong. No direct link between “inertia in the flow of water” and “inductance in pump’s circuit” ==> Out immediately.
D. Electrical engineers try to minimize the effects of inductance in electrical circuits
Wrong. Nothing about “engineers try to minimize the effect of inductance” ==> Out immediately.
E. When a water pump is switched off it continues to pump water for a second or two
Wrong. SHELL GAME. Fact #3 just says: inertia causes the decrease in the water flow to be gradual. Thus, E is wrong because:
(1) The stimulus does not mention how long a water pump continues to pump.
(2) You cannot infer “decrease in the water flow to be gradual” = 1 or 2 seconds. It may be 3 seconds, or even a minutes, who knows?
TAKEAWAY:
In "Must be true" question:
(1) No new info accepted.
(2) A correct answer MUST pass the fact test.
Hope it helps.