Question of the Day 25 Nov 2017

Neha's father was reading the manual of a camera which was in very small print. He was not able to read comfortably. Neha had two convex lens A and B of focal length 25 cm and 40 cm respectively. She gave the better of the two lenses to her father. He then read the manual comfortably without any strain in his eyes.

Now answer the following question.
(a) Which one of the two convex lenses did she gave to her father and why?
(b) What is the power of the lens A and B?
(c) What is the range of the distance that his father can keep the manual from the lens for comfortable reading?
(d) Unfortunately while handling the better of the two lenses, it got slipped from her father hand and broke into two piece. Will her father still be able to use the broken pieces for magnifying the small prints? 

Question of the day 15 Nov 2107

Question of the day 15 Nov 2017

A student has two resistors A and B of resistance 4 ohm and 6 ohm respectively.  The student was challenged by the Physics teacher to connect them to a 12 V battery so as to draw maximum current from the voltage source.

How would you advice the student to connect the resistors and what would be the current obtained?

Question of the day 14/11/2017

Question of the day - 14 Nov 2017

The resistance of an electric heating device is 20 ohms. If an electric current of 5 A flows through the device for 30 seconds. Determine

(i) Potential difference applied across the device.

(ii) heat produced in the device in 30 seconds.

QUESTION OF THE DAY 09/05/2015

Question of the day September 9, 2015

Three electric lamps A, B and C are rated as follows:

Lamp A : 40 W, 220 V

Lamp B: 60 W, 220 V and

Lamp C: 100 W, 220 V

Which lamp has higher resistance? Give reason.