Answer:
Explanation:
True
How well a material conducts current is an internal factor affecting resistance.A shorter wire will allow electricity to move through at a higher rate than a longer wire.When a light is first switched on, the light bulb's filament has a lower resistance than after it gives off light for awhile.Superconductors have no measurable resistance.If you double the thickness of a wire, you cut the resistance in half.A short, thick, cold wire is the best conductor.
False
Thickness, length, and temperature are internal factors that affect resistance.The resistance in a wire with less thickness is less.The higher the temperature of the conductor, the lower the resistance.If you double the length of a wire, you cut the resistance in half.
Metals can form a sea of elections which causes them to be good conductors of energy
Energy cannot be created or destroyed
I hope that helps
Answer:
Explanation:
In case of oil slick a thin layer of oil is formed on water . This thin layer creates a rainbow of colour . The phenomenon is due to interference of light waves , one reflected from the upper surface of oil and the other reflected from the lower surface of the oil.
For formation of bright colour
2 μ t = ( 2n + 1 ) λ / 2
μ is refractive index of oil , t is thickness of oil layer λ is wave length of light falling on the layer .
given μ = 1.2 , λ = 750 x 10⁻⁹ ,
2 x 1.2 t = ( 2n + 1 ) 750 x 10⁻⁹ / 2
For minimum thickness n = 0
2.4 t = 375 x 10⁻⁹
t = 156.25 n m
B ) If the refractive index of layer of medium below oil is less than that of oil , the condition of formation of colour changes
The new condition is
2 μ t = n λ
2 x 1.5 t = 750 nm , n = 1 for minimum wavelength .
t = 250 nm
C ) Light mostly transmitted means dark spot is formed at that point .
For that to be observed from water side , the condition is
2 μ t = ( 2n + 1 ) λ / 2
λ = 4μ t / ( 2n + 1 )
For maximum wavelength n = 0
λ = 4μ t
= 4 x 1.5 x 200 nm
= 1200 nm .