DP Physics (last assessment 2024)

Test builder »

Question 17N.3.SL.TZ0.8

Select a Test
Date November 2017 Marks available [Maximum mark: 8] Reference code 17N.3.SL.TZ0.8
Level SL Paper 3 Time zone TZ0
Command term Calculate, Identify, Show that, Sketch Question number 8 Adapted from N/A
8.
[Maximum mark: 8]
17N.3.SL.TZ0.8

A monatomic ideal gas is confined to a cylinder with volume 2.0 x 10–3 m3. The initial pressure of the gas is 100 kPa. The gas undergoes a three-step cycle. First, the gas pressure increases by a factor of five under constant volume. Then, the gas expands adiabatically to its initial pressure. Finally it is compressed at constant pressure to its initial volume.

(a)

Show that the volume of the gas at the end of the adiabatic expansion is approximately 5.3 x 10–3 m3.

[2]

Markscheme

500 000 × ( 2 × 10 − 3 ) 5 3 = 100 000 × V 5 3

V = 5.3 x 10–3 «m3»

Look carefully for correct use of pVγ = constant

(b)

Using the axes, sketch the three-step cycle.

[2]

Markscheme

correct vertical and horizontal lines

curve between B and C

 

Allow tolerance ±1 square for A, B and C

Allow ECF for MP2

Points do not need to be labelled for marking points to be awarded

(c)

The initial temperature of the gas is 290 K. Calculate the temperature of the gas at the start of the adiabatic expansion.

[2]

Markscheme

use of PV = nRT OR use of P T = constant

T = «5 x 290 =» 1450 «K»

(d)

Using your sketched graph in (b), identify the feature that shows that net work is done by the gas in this three-step cycle.

[2]

Markscheme

area enclosed

work is done by the gas during expansion

OR

work is done on the gas during compression

the area under the expansion is greater than the area under the compression

Syllabus sections