Index of refraction of a substance =
(speed of light in vacuum) / (speed of light in the substance)
Index in quartz = (2.9979 x 10⁸ m/s) / (2.0567 x 10⁸ m/s)
<em>Index = 1.4576 </em> (no units)
Answer:
(d) 2840 A
Explanation:
Threshold frequency can be be calculated using expresion below
(λ)= hc/ Φ
(λ) sodium/ (λ)tungsten = Φtungsten/ Φsodium
But (λ) sodium is given as 5460 A,
Φsodium = 2.3 eV
Φtungsten= 4.4 eV
If we substitute the values we can find
(λ)tungsten.
(λ)tungsten= [(λ) sodium × Φsodium]/ Φtungsten
=( 5460× 2.3)/4.4
= 2854A
Hence, threshold wavelength of tungsten is 2854A
I would go with C because all the rest of the answer are sitting on something.
3.4 miles/hour = 1519.936 mm/s