$gamma$ rays consists of
1). ?Meson particles?
2). Neutrino particles
3). Higg's boson?
4). ?Electromagnetic waves
1. The light of distant stars is affected by
2. In radio-communication, the signals emitted by transmitting antenna are reflected on
3. Alternating current is converted into direct current by a
4. The unit for measuring electric power is the
6. Permissible noise level at Residential area during night time Is:
7. The quality or tone of a musical sound produced by a stringed instrument depends on
8. Which of the following devices can be used to detect radiant heat ?
9. Instrument used to study the behaviour of a vibrating string is :