3 questions. Try each one, then open the answer to check yourself and read the explanation.
The electromotive force in the secondary winding of the transformer shown above is
Answer: C (increasing.)
The output (secondary) coil has more turns than the input coil, so the e.m.f. in the secondary is larger than the input voltage: a step-up transformer.
Calculate the temperature change when 500 J of heat is supplied to 100g of water.
Answer: C (1.2°C)
Δθ = Q/(mc) = 500 ÷ (0.1 × 4200) ≈ 1.2°C, using 4200 J kg−1 K−1 for water.
Which of the following is a correct explanation of the INERTIA of a body?
Answer: A (Reluctance to start moving once at rest and its reluctance to stop moving once it has begun to move)
Inertia is a body's tendency to keep its state: it resists being started when at rest and resists being stopped when moving.