ISC 2015 Physics Practical Question Paper for Class 12

About this paper

This is ISC Class 12 Physics Paper 2 (Practical), set by CISCE for the 2015 examination (paper code 861 B). It 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, and has three questions. Question 1 finds the focal length of a convex lens by the displacement method, plotting y = (x² − d²)/100 against x and using F = 25S. Question 2 finds the resistivity of a wire: a voltmeter and ammeter give its resistance at five settings of a resistance box, and a micrometer screw gauge gives its diameter. Question 3 is the assessment of the candidate's project and practical file by the Visiting Examiner.

Exam

ISC Class 12

Subject

Physics Practical

Year

2015

Paper code

861 B

Time allowed

3 hours + 15 min reading

Questions

3

Pages

4

Answers included

No, questions only

Paper pattern

• Question 1

  12 marks

  Focal length of a convex lens by the displacement method, with a graph of y against x

• Question 2

  8 marks

  Resistivity of a wire using a voltmeter, ammeter, resistance box and micrometer screw gauge (6 + 2 marks)

• Question 3

  10 marks

  Project (7 marks) and Physics practical file (3 marks) shown to the Visiting Examiner

Topics covered

• Focal length of a convex lens
• Displacement method
• Resistivity of a wire
• Least count of voltmeter, ammeter and screw gauge
• Graph plotting and slope of the line of best fit
• Project and practical file

Questions from this paper

1. Determine the approximate focal length of the given convex lens by projecting the image of a distant object on a wall or screen, and record it in cm correct to one decimal place.
2. Keeping the object pin and image pin a distance x ≈ (4f + 10) cm apart, find the two lens positions L₁ and L₂ that give a diminished and a magnified image, and record the displacement d of the lens.
3. Plot a graph of y = (x² − d²)/100 against x, determine the slope S of the line of best fit and calculate the focal length F = 25S.
4. With R = 1 Ω and the jockey at C so that AC = 80 cm, record the voltmeter and ammeter readings, then repeat for four more sets by increasing R by 1 Ω each time and find r = V/I for each set.
5. Determine the least count of the micrometer screw gauge, measure the diameter d of the specimen wire and calculate its resistivity using ρ = πd²r₀/320.