Showing posts with label class12-Physics. Show all posts
Showing posts with label class12-Physics. Show all posts

Saturday 14 October 2017

CBSE Class 12 - Physics - Chapter 9 - Electronics Devices - Revision Sheet (#cbseNotes)

CHAPTER 9 - ELECTRONIC DEVICES - REVISION ASSIGNMENT 

CBSE Class 12 - Physics - Chapter 9 - Electronics Devices - Revision Sheet (#cbseNotes)


1 MARK QUESTIONS

1.  In a semiconductor which of the following carries can contribute to the current?
(a) Electrons
(b) Holes
(c) Both
(d) None

2. A semiconductor diode has ______
(a) One PN junction
(b) Two PN junctions
(c) Three PN junctions
(d) Four PN junctions

3. If the arrow of diode symbol is positive with respect to bar, then the diode is ______ biased

4.  The DC resistance of a diode is _______ its AC resistance.

5. If the temperature of the diode increases,then leakage current ________.

Friday 8 September 2017

CBSE Class 10 - Light - Reflection From Mirrors (Worksheet) (#cbseNotes)

Light - Reflection From Mirrors (Worksheet)

CBSE Class 10 - Light - Reflection From Mirrors (Worksheet) (#cbseNotes)



1. We get a diminished image with a concave mirror when the object is placed ____.


2. The drivers mirror used in automobiles is ____.


3. The distance of focus F from the pole P is termed as the ..................... of the mirror.


4. Mirror formula is ____.


Wednesday 21 June 2017

Wednesday 24 May 2017

CBSE CLASS 12 - PHYSICS - RAY OPTICS AND OPTICAL INSTRUMENTS - Very Short Question Answers (#cbsenotes)

RAY OPTICS AND OPTICAL INSTRUMENTS

CBSE CLASS 12 - PHYSICS
CBSE CLASS 12 - PHYSICS - RAY OPTICS AND OPTICAL INSTRUMENTS - Very Short Question Answers (#cbsenotes)

Very Short Question Answers



Q1: What is the focal length and power of a plane glass plate?

Answer: Focal length of plane glass is infinite and its power = 0.


Q2: What is the mathematical relation between object distance (p) and image distance (i) in a plane mirror?

Answer: i = -p


Q3: An object is placed at the focus of  concave lens. Where will its image be formed? 

Answer: The real image will be formed at infinity.


Q4: If the speed of light were the same in all media, would refraction still occur when light passes from one medium to another? 

Answer: No change in speed of light causes bending of light rays in refraction.


Monday 15 May 2017

CBSE Class 12 - Physics -Syllabus and Q Paper Design (2017-18)

Physics -Syllabus (2017-18)


CBSE Class 12 Physics

CBSE Class 12 - Physics -Syllabus and Q Paper Design  (2017-18)

Here presents the prescribed syllabus for Class 12 Physics for the curriculum 2017-18.


Friday 31 March 2017

CBSE Class 12 - Physics - Electrostatic Potential and Capacitance (Short Q and A) (#cbsenotes)

Electrostatic Potential and Capacitance 

CBSE Class 12 - Physics 
(Short Q and A)
CBSE Class 12 - Physics - Electrostatic Potential and Capacitance (Short Q and A) (#cbsenotes)


Q1: Define Electrostatic Potential.

Answer: The electrostatic potential at a point is defined as amount of work done per unit positive test charge in moving the test charge from infinity to that point against the electrostatic force due to the electric field.
Q4: Is electric potential a scalar quantity or vector quantity?


Q2: Name the physical quantity whose SI unit is Joule coulomb⁻ⁱ?

Answer:  Electric potential


Q3: Does the electric potential increase or decrease along the electric line of force?

Answer: It decreases along the electric line of force.


Q4: Is electric potential a scalar quantity or vector quantity?

Answer: Scalar quantity


Wednesday 18 May 2016

Class 12 - Physics - Chapter 4: Moving Charges and Magnetism (VSQA)

Moving Charges and Magnetism

Very Short Q & A

Class 12 - Physics - Chapter 4: Moving Charges and Magnetism (VSQA)

Q1: Define Magnetic Field.

Answer: The space around a magnet within which its effect is experienced is called Magnetic Field (B).


Q2: What is the SI unit of magnetic field?

Answer: Tesla. Another unit is Newton Ampere-1 metre-1


Q3: What is a solenoid?

Answer: A solenoid is a circular coil of a large number of turns, such that the turns of solenoid run parallel to its length. It acts similar to a bar magnet.


Q4: What is Lorentz force?

Answer: The total force on a charge (q) moving with a velocity (v) in the presence of magnetic and electric field (B and F) respectively is called Lorentz force.


Q5: What is a cyclotron?

Answer: It is a machine to accelerate charged particles or ions to high energies


Q6: What is the operational definition of one ampere?

Sunday 20 March 2016

CBSE Class 12 - Physics - Electric Charges And Fields - Very Short Q and A

Electric Charges And Fields

Very Short Q and A

CBSE Class 12 - Physics - Electric Charges And Fields - Very Short Q and A
Charging By Induction
credits:openclipart


Q1: Define frictional electricity.

Answer: It is the electricity developed on bodies when they rubbed against each other.


Q2: What is the smallest amount of charge?

Answer: Charge on an electron or proton is ± 1.62 × 10-19 C


Q3: State the two basic properties of electric charge?

Answer:  i. Electric charge is quantised.
ii. Electric charge is always conserved.



Q4: Define Dielectric constant.

Answer: The Dielectric constant of a medium is the ratio of the force between two charges placed at a certain distance apart in vacuum(or air) to the force between the same two charges at the same distance apart in that medium.


Q5: What is induction?

Answer: It is a process of charging a body without making physical contact.


Tuesday 12 May 2015

CBSE Class 12 - Physics - CH3 - Current Electricity (NCERT Solutions)

Current Electricity

NCERT Solution 
CBSE Class 12 - Physics - CH3 - Current Electricity (NCERT Solutions)


Q1: The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4Ω, what is the maximum current that can be drawn from the battery?

Answer: Emf of the battery, E = 12 V
    Internal resistance of the battery, r = 0.4 Ω
    Maximum current drawn from the battery = I

   According to Ohm’s law,
          E = Ir
          I = E/r  = 12/0.4 = 30 A
   Thus, the maximum current drawn from the given battery is 30 A.


Q2: A battery of emf 10 V and internal resistance 3 Ω is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?

Answer: Given,
                Emf of the battery, E = 10 V
                Internal resistance of the battery, r = 3 Ω
                Current in the circuit, I = 0.5 A
                Resistance of the resistor = R
       Applying Ohm’s law,
                I = E/(R + r)
           R + r = E/I  = 10/0.5 = 20 Ω
           ∴ 20 - 3 = 17 Ω

       Terminal voltage of the resistor = V
       According to Ohm’s law,
                    V = IR = 0.5 × 17 = 8.5 V
       ∴ the resistance of the resistor is 17 Ω and the terminal voltage is 8.5 V.

Q3: a) Three resistors 1 Ω, 2 Ω, and 3 Ω are combined in series. What is the total resistance of the combination?
       b) If the combination is connected to a battery of emf 12 V and negligible internal resistance, obtain the potential drop across each resistor.

Answer:
    (a) Three resistors of resistances 1 Ω, 2 Ω, and 3 Ω are combined in series.
         Total resistance of the series combination is the algebraic sum of individual resistances.
         ⇒ Total resistance = 1 + 2 + 3 = 6 Ω