A Ramesh while doing his physics practical in a class, found that if a voltmeter, an ammeter and a resistance are connected in series to a lead accumulator, there is deflection in the voltmeter but the deflection in ammeter is negligible. He discussed his problem with all his class fellows but no one could explain the reason. Harshpreet was also studying in his class. When he discussed the problem with her, she explained the reason and then whole class was informed by both of them.
(a) What was the reason for deflection in voltmeter and negligible deflection in the ammeter?
(b) What value were displayed by Ramesh and Harshpreet?

Rahul after having lived in US for 12 years returned back to India. He had a discussion with his cousin Sumit on domestic power supply in US and in India.In US domestic power supply is at 110V, 50Hz, whereas in India it is 220V, 50Hz.. Rahul was stressing that US supply is better than Indian supply. Both went to Sumit's father an electrical Engineer and asked his opinion on the issue. He explained that both the supplies have advantages as well as disadvantages.
1. What values are used by Rahul and Summit?
2. Write one advantage and one disadvantage of 220V supply over 110V supply.

Two boys, on their way from school were discussing seriously about something. They both were blowing soap bubbles and were thrilled to watch the expanding bubble with spectacular colour rings. Rita, a class XII student, was watching them for a long time, walking behind them. Suddenly she realised that the kids did not look at the traffic in that junction area. She rushed to them and instructed them to be cautious while on the road. She also explained the importance of traffic rules and told them that obeying traffic rules not only makes us safe but also others safe.
(i) What are the values highlighted by Rita
(ii) why are colours formed on bubbles?

Modulation is the phenomenon of superimposing the low audio frequency base band message or information signals (called the modulating signals) on a high frequency wave (called, the carrier wave). The resultant wave is called the modulated wave, which is transmitted.
Read the above passage and answer the following questions:
(i) What are the Audio frequency and Radio Frequency ranges?
(ii) Why audio frequency signals, as such cannot be transmitted over long distances?
(iii) What does the phenomenon imply in day to day life?

Demodulation is the reverse process of modulation, which is performed in a receiver to recover the original modulating signals. At the receiving end, the signals are generally weak due to attenuation in the channel. The receiver selects only the desired signal, rejecting the unwanted (noise) signals and amplifies the same.
Read the above passage and answer the following questions:
(i) What are the main functions of a demodulator?
(ii) Give any two examples of demodulators.
(iii) What does the phenomenon of demodulation imply in day to day life?