Question

There is some water in the beaker placed on the pan of a spring balance. If we dip our finger in the water without touching the bottom of the beaker, then what is the change in the reading of spring balance?

• A. The reading increases.
• B. The reading increases twice.
• C. The reading remains unaffected.
• D. The reading decreases.

Answer 1

The correct option is A

The reading increases.

When we dip our finger in the water, the water exerts upward thrust on the finger (Archimedes's principle). Due to Newton's third law of motion, the finger will exert an equal and opposite force on the water in downward direction resulting in increase of the weight of water. Thus the reading of the spring balance will increase.