Answer:
The magnetic field at a distance of 19.8 cm from the wire is 1.591 mT
Explanation:
Given;
first magnetic field at first distance, B₁ = 2.50 mT
first distance, r₁ = 12.6 cm = 0.126 m
Second magnetic field at Second distance, B₂ = ?
Second distance, r₂ = ?
Magnetic field for a straight wire is given as;

Where:
μ is permeability
B is magnetic field
I is current flowing in the wire
r distance to the wire

Therefore, the magnetic field at a distance of 19.8 cm from the wire is 1.591 mT
the answer for the question is D. all of the above
Answer:
Option B. They use thermal updrafts to stay aloft
Explanation:
The sunlight warms the surface of the earth during noon and morning time and when this warming of the Earth's surface is not evenly done or uniform then this gives rise to the thermals. These are the rising air columns and rises when the air nearest to the earth heats up.
This is how some birds like vultures make use of the thermal updrafts to maintain flight.