Answer:
a).
S.I units of length is meters. So we've to change cm → m
b).
km → m
Answer:
A radioactive element or radioactive substance have a half life
Explanation:
The half life of a radioactive element is defined as the time taken for the atoms of the radioactive elements to decay to half the original number
Radioactive decay
Radioactive decay simply the process by which the nucleus of a heavy radioactive element disintegrates and emits alpha or beta particles along with Gama rays
Law of radioactivity
The law states that when a radio active element decays or disintegrates it forms a new element two places below in the periodic table with emission of alpha particles or two places above the element in the periodic table with emission of beta particle.
Answer:
D) Erosion and Weathering
Explanation:
Erosion forces rocks to crash together or crack apart, some rocks shatter and crumble, while others are worn away.
During erosion, exfoliation which is a type of weathering occurs in sheets along joints/ lines which runs throughout Stone Mountain. Once a sheet on the surface has been exfoliated and the sheet of rock beneath it is exposed the process begins again. This process gradually changes the way Stone Mountain looks.
Answer:
The magnetic force is 0.3 N.
Explanation:
Given that,
Current in an unusual lightning strike, I = -400 A
The Earth’s magnetic field at that location is parallel to the ground and has a magnitude of 30 μT, 
We need to find the force exerted by the Earth’s magnetic field on the 25 m-long current.
The magnetic force is given by :
So, the magnetic force is 0.3 N.
Answer:
answer below
Explanation:
Displacement of the student is 739 m due North and it takes 162 s.
We need to find the student's average velocity. Using formula of velocity.
Velocity = displacement/time
v= 739/162
v= 4.56
