Q151 · Practice questionComplex familiar1 mark
QUESTION 151
A probe travels at relative to a laboratory and emits simultaneous forward and backward pulses of light in vacuum. Which speeds does the laboratory measure for the two pulses?
(A)
forward and backward
(B)
in each direction
(C)
in each direction
(D)
forward and backward
WORKED SOLUTION
1 markAnswer B
ANSWER
B. in each direction
Worked solution
The speed of light in vacuum is c in every inertial frame, regardless of source motion. The pulse velocities have opposite directions, but equal speed.
Equivalent physically justified methods and consistent equivalent units accepted.
Displayed decimals are model answers; accept appropriate significant figures and consistent rounding from stated constants.
Select B.
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
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