ISC 2018 Physics Practical Question Paper for Class 12

About this paper

This is ISC Class 12 Physics Paper 2 (Practical), set by CISCE for the 2018 examination (paper code 861B). It carries 30 marks and runs for three hours plus fifteen minutes of reading time, with no more than one and a half hours to be spent on each experiment. Question 1 is based on the Wheatstone bridge principle: balancing lengths on a metre bridge for x = 1 Ω to 6 Ω give y = l/(100 − l), and the slope S of the y–x graph gives R = 1/S for a coiled wire. Question 2 finds the focal length of a convex lens by the no parallax method using p = 100/u, q = 100/v and f = 100/(p + q). Question 3 is the assessment of the project and practical file by the Visiting Examiner.

Exam

ISC Class 12

Subject

Physics Practical

Year

2018

Paper code

861B

Maximum marks

30

Time allowed

3 hours + 15 min reading

Questions

3

Pages

4

Answers included

No, questions only

Paper pattern

• Question 1

  9 marks

  Resistance of a coiled wire by the Wheatstone bridge principle, with a graph of y against x

• Question 2

  6 marks

  Focal length of a convex lens by the no parallax method, five object distances

• Question 3

  15 marks

  Project (10 marks) and Physics practical file (5 marks) shown to the Visiting Examiner

Topics covered

• Wheatstone bridge and metre bridge
• Resistance of a coiled wire
• Focal length of a convex lens
• No parallax method
• Graph plotting and slope of the line of best fit
• Project and practical file

Questions from this paper

1. Keeping E at 2 V, take out a 1 Ω plug from the resistance box so that x = 1 Ω, and find the balancing length AC = l at which the galvanometer shows no deflection, correct to one decimal place.
2. Repeat the experiment for x = 2 Ω, 3 Ω, 4 Ω, 5 Ω and 6 Ω, and for each value calculate y = l/(100 − l) correct to two decimal places.
3. Plot a graph of y against x, draw the best fit line, determine its slope S to three significant figures and calculate R = 1/S with its unit.
4. With the object pin at the 0.0 cm mark and the lens at the 30.0 cm mark, remove the parallax and record the image distance v; repeat for u = 40.0 cm, 50.0 cm, 60.0 cm and 70.0 cm.
5. For each value of u, calculate p = 100/u, q = 100/v and f = 100/(p + q), and find F, the mean value of f.