The potential difference across resistor R2 is measured as 4 V. Calculate the:
Emf of the battery

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Iron reacts with sulfur to form iron sulfide. if 60 grams of iron reacts with sulfur to produce 90 grams of iron sulfide, how much sulfur has been used in the chemical reaction?

What are the similarities & differences between a thermistor and a light dependent resistor in physics?

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?