That's false. Mechanical waves (like sound and ocean waves) do
need a medium to travel in, but electromagnetic waves (like radio
and light) don't.
Answer:
Magnetism is the force exerted by magnets when they attract or repel each other.
Answer:
(1) An object that’s negatively charged has more electrons than protons.
(2) An object that’s positively charged has fewer electrons than protons.
(3) An object that’s not charged has the same number of electrons than protons.
Explanation :
Objects have three subatomic particles that are Electrons, protons, and neutrons.
Protons and neutrons are found in the nucleus and electrons rotate or move outside the nucleus. Naturally, protons are positively charged, neutrons have no charge, and electrons are negatively charged.
Therefore, an object that is negatively charged has more electrons than protons. An object that is not charged has the same number of electrons than protons. An object that is positively charged has fewer electrons than protons.
Explanation:
(9) Acceleration due to gravity is defined as the acceleration between two massive bodies when they are moving under free fall.
The relation between g and G is given by :
Where
G is universal gravitational constant
M is mass of the earth
r is distance
(10) The unwanted product that can toxify the crops are called weeds. To control weeds, a chemical called weedicides are sprayed in the field. Some other methods to control them are Ploughing or tilling of soil etc.
