Answer:
B = 0.126 T
Explanation:
As per Faraday's law we know that rate of change in magnetic flux will induce EMF in the coil
So here we can say that EMF induced in the coil is given as
initially the coil area is perpendicular to the magnetic field
and after one fourth rotation of coil the area vector of coil will be turned by 90 degree
so we can say
now we will have
Answer:
hmm
Explanation:
By increasing the number of turns in the coil, strength of magnetic field, speed of rotation of the coil in the magnetic field and by decreasing the distance between the coil and the magnet the magnitude of the induced e.m.f. can be increased in generator/dynamo.
Pic of Bohr Model attached
Answer: The poker stick should have low thermal conductivity and high specific heat.
Explanation: For a poker stick that is non flammable, it should have some properties which will not let it heat up faster.
Two properties that satisfy the poker stick are:
- Specific heat
- Thermal conductivity
Specific heat is defined as the amount of heat require to raise the temperature of a mass M by 1 °C. More the specific heat, more amount of heat will be required to raise the temperature of a substance.
Thermal conductivity is defined as the ability of a substance to conduct heat. More thermal conductivity means that the substance will get hot faster as it will conduct more amount of heat.
So, for a substance that should not conduct more heat like the poker stick must have high specific heat and low thermal conductivity.
Answer:
The oldest stars in spiral galaxies are younger than the oldest stars in elliptical galaxies.
Explanation:
Spiral galaxies have a greater star formation than elliptical galaxies, since the latter contain less gas and dust. Therefore, the rate of creation of new stars is lower in elliptical galaxies. These galaxies are dominated by old stars, with a long evolution. While the spiral galaxies have stars with a faster evolution.
