Srijit Chatterjee − Profile

In place of cosmic rays, I think Gamma rays would be more appropriate.

Nichrome

(Nichrome has a high melting point and offers low resistivity to current and gets heated easily)

Filament of an electric bulb is made of tungsten.

(Tungsten has a very high melting point of about 3695 K and glows brightly on getting heated)

Copper is used in connecting wires.

(It has a high conductivity and therefore offers low resistance to the flow of current)

Resistance of a conductor depends on:

1. Material of the conductor (resistivity): Higher resistivity implies higher resistance

2. Length of the conductor: Reistance increases with increase in length of conductor

3. Area of cross section of the conductor: Resistance decreases with increase in area of cross section of the conductor.

RI of water = (real depth)/(apparent depth)

                   =15/(15-3.75)

                   =1.33

(Remember refractive index is unitless as it is the ratio of velocity of light in two optical media)

Concave Lens

For the ray to pass undeviated, the angle of incidence, i = 0 (in degree)

1. ring - at the centre of the ring

2. rhombus - at the point of intersection of the two diagonals

1 N = 10^5 dyne

(newton (N) is the SI unit of force and dyne is the SI unit of force)