MCQ
A barometer kept in an elevator reads $76 \,cm$ when it is at rest. If the elevator goes up with some acceleration, the reading will be .......... $cm$
- A$76$
- B$>76$
- ✓$<76$
- D$0$
✓
Answer
Correct option: C.
$<76$
c
(c)
(c)
When elevator goes up with some acceleration upward, due to pseudo force acting downwards. Value of $g$ increases to $g^{\prime}$.
If $g$ increases to $g^{\prime}$,
$\text { i.e., } g^{\prime}=g+a$
$\because P=\rho g h=\rho(9+a) h h^{\prime}=$ constant
Then, $h^{\prime} < h$
i.e., $h^{\prime} <76 \,cm$
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