The refractive index of glass is 1.520 for red light and 1.525 for blue light. Let D1 and D2 be an of minimum deviation for red and blue light respectively in a prism of this glass. Then
D1 > D2
D1 < D2
D1 = D2
D1 = D2
A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold then, an electric current will
flow from Antimony to Bismuth at the cold junction
flow from Antimony to Bismuth at the hot junction
flow from Bismuth to Antimony at the cold junction
flow from Bismuth to Antimony at the cold junction
The time by a photoelectron to come out after the photon strikes is approximately
10−1 s
10−4 s
10−10 s
10−10 s
An alpha nucleus of energy 1 /2 mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to
1/Ze
v2
1/m
1/m
The energy spectrum of β-particles [number N(E) as a function of β-energy E] emitted from a radioactive source is
When 3Li7 nuclei are bombarded by protons, and the resultant nuclei are 4Be8 , the emitted particles will be
neutrons
alpha particles
beta particles
beta particles
A solid which is transparent to visible light and whose conductivity increases with temperature is formed by
Metallic binding
Ionic binding
Covalent binding
Covalent binding
If the ratio of the concentration of electrons that of holes in a semiconductor is 7 /5 and the ratio of currents is 7/4, then what is the ratio of their drift velocities?
4/7
5/8
4/5
4/5
D.
4/5
In a common base mode of a transistor, t collector current is 5.488 mA for an emit current of 5.60 mA. The value of the base current amplification factor (β) will be
48
49
50
50
The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows