MCQ
A barometer kept in an elevator reads 76cm when it is at rest. If the elevator goes up with increasing speed, the reading will be:
- Azero.
- B76cm.
- ✓< 76cm.
- D> 76cm.
✓
Answer
Correct option: C.
< 76cm.
If the elevator goes up at an increasing speed, then the effective value of g increases.
We know:
P = ρgh.
So, h will have a lesser value for the same value of P if g increases.
We know:
P = ρgh.
So, h will have a lesser value for the same value of P if g increases.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
In a parallel beam of white light is incident on a converging lens, the colour which is brought to focus nearest to the lens is
If ${R_p} = 7K\Omega ,\,{g_m} = 2.5 \Omega$ millimho, then on increasing plate voltage by $50\,V$, how much the grid voltage is changed so that plate current remains the same.......$V$
→N identical spherical drops charged to the same potential V are combined to form a big drop. The potential of the new drop will be
Which of the following phenomena can be demonstrated by light. But not with sound waves in an air column?
Assertion : In photoemissive cell inert gas is used.
Reason : Inert gas in the photoemissive cell gives greater current.
Reason : Inert gas in the photoemissive cell gives greater current.
Same current i = 2A is flowing in a wire frame as shown in figure. The frame is a combination of two equilateral triangles ACD and CDE of side 1m. It is placed in uniform magnetic field B = 4T acting perpendicular to the plane of frame. The magnitude of magnetic force acting on the frame is
In Boolean algebra $A.B=Y$ implies the :
→Current is flowing in a circular coil of radius r. There are n turns in the coil. Its magnetic moment varies with r. As:
If the dipole with charges $\pm q$ are kept perpendicular to each other inside a closed cube, then the total electric flux emerging out of the cube will be:
→In a parallel plate capacitor of capacitance $C$, a metal sheet is inserted between the plates, parallel to them. If the thickness of the sheet is half of the separation between the plates. The capacitance will be
→