Physics (Part-VII) (Railway)

• When a ray of light enters the glass prism it gets deviated two times.

• First when it enters the glass prism and second when it comes out of the prism. Also, when the ray of light passes through the prism it bends towards its base.

• Light ray travels from rarer medium to denser medium, Angle of refraction is smaller than angle of incidence at AB.

• at AC, a ray of light travels from a denser medium and into a rarer medium, the angle of incidence is smaller than the angle of refraction.

• Optical centre is the point through which any ray passes undeviated.

• It always lies inside the lens and not on the surface.

• Therefore, the dust particles and water molecules present in clouds scatter all color of Incident white light from sun by about the same amount.

• Light of all wavelengths are scattered equally and hence clouds appear white.

• Hence the image is formed at infinity.

• Hence, with increase in distance the magnetic field will decrease and vice versa.

• So, when the current passing through a conductor is doubled and the potential difference is tripled then the power will increase 3 * 2 = 6 times

• So, according to the question, 1 / R = 1/10 + 1/15 + 1/30 = 6/30

• R = 5 Ω

The thumb, forefinger and central finger of left hand are mutually perpendicular (90°) to each other.

• Thumb points towards the direction of force.

• Middle finger represents the direction of the current.

• Index finger represents the direction of the magnetic field.

• So, according to the question, 1 / R = 1/6 + 1/9 + 1/6 = 3 + 2 +3/18=8/18

? R = 18/8 = 2.5 Ω

1/R₁ = 1/R₁ + 1/R₂ + 1/R₃

• For series connection, the resultant resistance = R₁ +R₂ +R₃