151: flux per unit volume is called
a) Curl
b) Gradient
c) Divergence
d) None of these
152: point form of gauss’s law
a) ∇.D=ρV
b) ∇.D=ρS
c) ∇.D=ρV/ε°
d) ∇.D=Q
153: A charge density of 10 nC /m2
is distributed on a plane Z =10m the electric field
intensity at the origin is
a) -18πaz v/m
b) -10πaz v/m
c) -360πaz v/m
d) -18πaz v/m
154: if the electric field intensity is 1v/m in free space the energy density is
a) 4.427 PJ/m3
b) 8.854 PJ/m3
c) 4.427 PJ
d) 8.854 PJ
155: the work done in carrying a charge Q once around a circle of radius ‘r’ with charge Q at
the centre is
a) qQ4πε°r
b) qQ4πε° 1πr
c) qQ4πε° 12πr
d) Zero
156: Gauss’s law is
a) D.ds=Qb) D.ds=Q
c) D.ds=Q
d) D.ds=Q
157: the equation of continuity is
a) J.ds=I
b) Jds=I
c) J.ds=Q
d) J.ds=Q
158: In dielectric
a) ρv dv=Qb
b) ρb dv=-Qb
c) ρ dv=Qb
d) ρp dv=Qb
159:7 In planks apparatus the photo emissive cell has spectral response between?
a) 145 to 635 mm
b) 185 to 650 pm
c) 165 to 732 um
d) 185 to 650 nm
160: In plank’s constant (new apparatus) the value of dark current should be………….micro
Ampere
a) less than 0.003
b) Greater than 0.003
c) In between
d) None of these
161: Write down the formula to count the e/m ratio of electron ( for new apparatus )
Ans:
162: in e/m experiment the number of turns of the solenoid?
a) 104
b) 106
c) 10d) 102
163: One Tesla is equal to
a) 104 Guass
b) 106 Guass
c) 10-4 Guass
d) 10-6 Guass
164: The wavelength of orange filter which is used in plank’s constant experiment is
a) 620 nm
b) 620 micro m
c) 530 nm
d) none of these
165: The red colour has the largest wavelength of all the seven colour spectrum, has
the………… deviation
a) Least
b) Greatest
c) both a & b
d) none of these
166: The thickness of Lee disk……mm
a) 25.32
b) 26.32
c) 30.32
d) 23.32
167: The semiconductor laser diode used in the experiment of measurement of sugar concentration in a liquid has maximum energy
a) 1mJ/s
b) 1mW
c) 1mJ
d) both a & b
168: The refractive index of 10% sugar solution is
a) 1.522
b) 1.436
c) 1.347
d) 1.20
169: The unit of conductivity is
a) ohm meter
b) ohm m2
c) ohm-1m-1
d) ohm m-1
170: the unit of thermal conductivity is
a) W m k
b) W m2 k
c) W/m k
d) W/m2 k
