DP Physics (last assessment 2024)

Test builder »

Question 18N.2.HL.TZ0.7b

Select a Test
Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.2.HL.TZ0.7b
Level HL Paper 2 Time zone TZ0
Command term Determine Question number b Adapted from N/A
b.
[Maximum mark: 2]
18N.2.HL.TZ0.7b

A small electric motor is used with a 12 mF capacitor and a battery in a school experiment.

When the switch is connected to X, the capacitor is charged using the battery. When the switch is connected to Y, the capacitor fully discharges through the electric motor that raises a small mass.

(b)

The motor can transfer one-third of the electrical energy stored in the capacitor into gravitational potential energy of the mass. Determine the maximum height through which a mass of 45 g can be raised.

[2]

Markscheme

energy stored in capacitor « 1 2 CV2 or 1 2 QV =»  1 2  × 12 × 10−3 × 7.52 «= 0.338 J» ✔

height = « 1 3 × 0.338 9.81 × 4.5 × 10 − 2 = » 0.25/0.26 «m»

 

Allow use of g = 10 m s−2 which gives 0.25 «m»

Syllabus sections