Select the Transformer tab, which contains an electromagnet at left (containing a DC battery) and a pickup coil attached to a light bulb at right. The electromagnet produces a magnetic field very similar to that of the bar magnet. Try to find a location where the stationary electromagnet (with a DC current) induces a current in the pickup coil and causes the light bulb to shine. Which of the following is correct?
1. There is no induced current in the coil, so the light bulb does not shine, if the electromagnet is stationary (for any location of the electromagnet)
2. The light bulb shines due to an induced current if one pole of the electromagnet is near the middle of the coil.
3. The light bulb shines due to an induced current if the electromagnet is inside the coil.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.

a sonic boom is a loud boom that breaks the sound barrier

explanation: