A student investigates electrostatic phenomena using an acrylic ruler and a polyester cleaning cloth.
Explain in terms of electrons why the acrylic ruler is initially electrically neutral.
Explain in terms of electrons why the ruler acquires a net negative charge when the student rubs it vigorously with the polyester cloth.
The diagram shows the electric field between two point charges, A and B.
State the signs of the charges A and B. Use the direction of the electric field lines in the diagram to explain your answer.
Describe one similarity between this electric field line diagram and a magnetic field line diagram between two opposite magnetic poles.
Calculate the charge when 840 J840\text{ J}840 J of energy is transferred with a potential difference of 24 V24\text{ V}24 V.
Use the equation: energy transferred=charge×potential difference\text{energy transferred} = \text{charge} \times \text{potential difference}energy transferred=charge×potential difference