Question

It is observed that when a brush is rubbed over a woollen towel and then taken near a stream of flowing water, the water stream bends towards the brush. Which of the following might be the reason for it?

• A. Electrostatic discharge from the tap
• B. Magnetic attraction by the charged brush
• C. Water flowing under gravity acquires magnetic properties
• D. Electrostatic force between the brush and the stream

Answer 1

The correct option is D Electrostatic force between the brush and the stream

As the brush is rubbed with the woollen towel, it acquires electrons that gets rubbed off from the atoms of the towel. In a liquid like water, the molecules are free to re-orient themselves. So, when the negatively charged brush is brought near the positively charged part of the molecules i.e. hydrogen, atoms align themselves towards the brush. Since unlike charges attract, the waterflow bends towards the brush.