A converging lens has a focal length of 15 cm and an object stands 20 cm from it. How far from the lens does the real image form?
Answer and explanation
Correct answer: A. 60 cm
- Step 1: Lens equation: 1/v = 1/f - 1/u = 1/15 - 1/20 = 1/60. Step 2. v = 60 cm. Answer: 60 cm. Why not the others: 5 cm subtracts the distances, 35 cm adds them, and 8.6 cm adds the reciprocals instead of subtracting.
Practise more Quantitative science problems.
Free questions with an explanation for every one, and full timed GAMSAT (Graduate Medical School Admissions Test) mock tests.
More Quantitative science problems questions
- A ball is thrown at 30 m/s at 45° to the ground. Taking m/s², what is its horizontal range?
- A simple pendulum has length 3.6 m. Taking m/s², what is its time period?
- Two point charges of 6 μC and 2 μC are placed 0.2 m apart in air. Taking N m²/C², what is the force between them?
- Capacitors of 3 μF and 4 μF are joined in series. What is the equivalent capacitance?
- How much energy is stored in a 4 μF capacitor charged to 10 V?
- Photons of energy 5 eV fall on a metal of work function 1.5 eV. What is the maximum kinetic energy of the emitted photoelectrons?