Answer:
A. rods in the retina of the human eye
Explanation:
Violet : The shortest wavelengths are perceived as violet and the longest wavelengths are perceived as red.<span />
Answer:
Explanation:
Magnitude of force per unit length of wire on each of wires
= μ₀ x 2 i₁ x i₂ / 4π r where i₁ and i₂ are current in the two wires , r is distance between the two and μ₀ is permeability .
Putting the values ,
force per unit length = 10⁻⁷ x 2 x i x 2i / ( 6 x 10⁻³ )
= .67 i² x 10⁻⁴
force on 3 m length
= 3 x .67 x 10⁻⁴ i²
Given ,
8 x 10⁻⁶ = 3 x .67 x 10⁻⁴ i²
i² = 3.98 x 10⁻²
i = 1.995 x 10⁻¹
= .1995
= 0.2 A approx .
2 i = .4 A Ans .
Answer : 
Explanation :
Given that,
Charge of particle 1 = 
Distance x = 6 cm
Charge of particle 2 = 
Distance x = 27 cm
Total distance = 

Particle 1 is at (6,0) and particle 2 is at (27,0) .
Therefore, midway (16.5, 0)
Now, 
Formula of electric field

Now, the the electric field due to particle 1



Similarly, the electric field due to particle 2

Resultant Electric field


Hence, this is the required answer.