Monthly Archive: February 2011
Some Guidelines For students appearing for class XII Physics Board Exams.
Answering 5 marks questions
CBSE gives two options for each five marks questions.
You have to be wise while selecting the question for answering. In some cases, one option will carry a “describe the principle construction and working” type and the other may be a combination
Permanent link to this article: http://www.plustwophysics.com/be-wise-while-selecting-five-marks-questions/
(This is being posted as per request from students)
Consider a conductor of length l and area of cross section A. Let the number of free electrons per unit volume be n. When a pd V is applied, let the
Permanent link to this article: http://www.plustwophysics.com/derive-an-expression-for-current-in-terms-of-drift-velocity-derive-i-naev/
Do you know? There are almost always some questions asked from these portions.
Photoelectric effect (Please learn the full portion)
Logic gates (please learn full as per syllabus)
Permanent link to this article: http://www.plustwophysics.com/aissce-physics-2011-sure-shot-questions-some-suggestions/
(This is one of the Expected Question for AISSCE Physics 2011)
Explain the action of transistor as a switch.
To answer this question (with proper understanding) you should have an idea of the three regions
Permanent link to this article: http://www.plustwophysics.com/transistor-as-a-switch/
Permanent link to this article: http://www.plustwophysics.com/beats-animation/
Permanent link to this article: http://www.plustwophysics.com/collection-of-cbse-class-12-previous-question-papers/
Physics 2004 Set 1
- Why is shortwave band used for long distance radio broadcast?
- Two metals A and B have work functions 2 eV and 5 eV respectively. Which metal has lower threshold wavelength?
- Draw the voltage-current characteristic of a zener diode.
- A solenoid with an iron core and a bulb is connected to a d.c. source. How does the brightness of the bulb change when the iron core is removed from the solenoid?
- Peak value of e.m.f of an a.c. source is E0. What is its r.m.s value?
- An electric dipole of length 4 cm, when placed with its axis making an angle of 60° with a uniform electric field, experiences a torque of Nm. Calculate the (i) magnitude of the electric field (ii) potential energy of the dipole, if the dipole has charges of ± 8 nC.
- Explain how the resistivity of a conductor depends upon (i) number density ‘n’ of free electrons, and (ii) relaxation time ‘λ’.
- Two long parallel straight wires X and Y separated by a distance of 5 cm in air carry currents of 10 A and 5 A respectively in opposite directions. Calculate the magnitude and direction of the force on a 20 cm length of the wire Y.
Permanent link to this article: http://www.plustwophysics.com/class-xii-physics-cbse-2004-board-question-paper/