Radio waves, Middle-C, and halitosis are not forms of light.
Answer:
The number of free electrons per cubic meter is 
Explanation:
It is given that,
The number of free electrons per cubic meter is, 1.3
Electrical conductivity of metal, 
Density of metal, 
Atomic weight, A = 107.87 g/mol
Let n is the number of free electrons per cubic meter such that,


Where
is the density of silver atom
is the Avogadro number
A is the atomic weight of silver


or

Hence, this is the required solution.
Answer:
first lens v = 48 cm
second lens v = -15.6 cm
magnification = 1.67
final image is virtual
and final image is upright
Explanation:
given data
distance = 16 cm
focal length f1 = 12 cm
focal length f2 = 10.0 cm
to find out
location of the final image and magnification and Type of image
solution
we apply here lens formula that is
1/f = 1/v + 1/u .....................1
put here all value and find v for 1st lens
1/12 = 1/v + 1/16
v = 48 cm
and find v for 2nd lens
here u = 20- 48 = -28
- 1/10 = 1/v - 1/28
v = -15.6 cm
and
magnification = first lens (v/u) × second lens ( v/u)
magnification = (-15.6/-28) × ( 48/16)
magnification = 1.67
so here final image is virtual
and final image is upright