The sharp point of a pin is brought near the cap of a negatively charged electroscope .State and explain the observation made on the leaf of the electroscope

K.C.S.E Physics Q & A - MODEL 2018PP2QN10

The sharp point of a pin is brought near the cap of a negatively charged electroscope .State and explain the observation made on the leaf of the electroscope

answer

• The leaf collapses 
• Negative charge is induced on the tip of the pin. Pin repels negatively charged air ions which discharges the electroscope.