1. A Semi conductor acts as an insulator at – 0 K
2 The laser which helped to prove that the velocity of light is the same in all directions
is – He-Ne laser
3. The value of the magnetic permeability of free space µo = 4 π ×10-7 H/m
4 The velocity V of a sound wave of frequency (n) and wave length (λ) is given by – v = nλ
5 In a p-type semi conductor majority carriers are – holes
6 1 Calorie = 4.2 J
7 Deep Water region behaves as a – Rarer medium
8 The units of Intensity of magnetisation are – Tesla
9 β- Particles are – Electrons
10 Neptunium series is a – 4n+1 series
11 The radius of nucleus of an atom is – 10-13cm
12 A transformer works on the principle of – Mutual induction
13 The unit of B in S.I. System is – N/A-m
14 Refining and extraction of metals is – Metallurgy
15 The least count of a screw gauge when the pitch of the screw is 0.5 mm and the total no. of divisions on the head is ‘100’ is – 0.005 mm
16 An example for diamagnetic substance is – Bi
17 Distance between two successive nodes is- λ/2
19 The energy gap is highest in the case of – insulator
20 Which one of the following is not a diamagnetic substance- Iron
21 In a stationary wave, the points at which the displacement is minimum are called – Nodes
22 Mass Energy relationship is E= mC2
23 Quantum theory was proposed by – Max Planck
24 The unit of electric current is – Ampere
25 The unit of ‘pole srength’ in S.I. units is – Ampere – metre