Coherent and incoherent addition of waves

If the waves are coherent, then the resultant intensity is given by I = I1 + I2 + 2 √(I1 I2 Cos Θ), where Θ is the phase difference between two waves. For the constructive interference the value of Θ = 0°, so that the Cos Θ = 1 and for the destructive interference the value of  Θ = … Continue reading Coherent and incoherent addition of waves

Electrostatics : A Practice Test Paper – 1

Time: 45 min Max. Marks: 25 How does the force between two point charges change, if the dielectric constant of the medium in which they are kept, increases? [1] Name the experiment which established the quantum nature of electric charge. [1] Ordinary rubber is an insulator, but the special tyres of aircrafts are made slightly conducting. Why … Continue reading Electrostatics : A Practice Test Paper – 1

Class XII Physics SOME QUESTIONS FROM CBSE 2004 Board Question Paper

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 … Continue reading Class XII Physics SOME QUESTIONS FROM CBSE 2004 Board Question Paper

Some sample questions from Physics for SA 2 of CCE class X

List the three phenomenon responsible for the formation of rainbow. (Ans: Refraction, Dispersion, (Total)Internal reflection) Why do stars twinkle, but planets do not? (Ans: The twinkling is caused by the variation of intensity of light entering our eye from the stars. The starts are far away from us and they are seen in a position different from their … Continue reading Some sample questions from Physics for SA 2 of CCE class X

Interference is in complete agreement to law of conservation of energy

Tilak gurjar posted; "Interference is in complete agreement to law of conservation of energy. Comment" Answer: If there were no interference, the resultant intensity at a point illuminated by two sources will be I = I1+I2 Due to interference This shows that energy is conserved even after interference. There is only a redistribution of energy. There … Continue reading Interference is in complete agreement to law of conservation of energy