41.A telephone receiver consists of a permanent magnet with wires around it and a metal diaphragm in front of the magnet. 1. The current in the wire neutralises completely the field of the permanent magnet. 2. The current in the wire adds a small component to the field of the magnet. 3. The diaphragm rotates due to the signal. 4. The diaphragm vibrates due to the signal. Choose the correct combination of statements

42.Which of the following is a good nuclear fuel ?

43.Three important micronutrients essential for humans are

44.Wisdom teeth normally grow during the age of

45.Gypsum is added to cement clinker to