Similar elements with similar properties were in the same groups and periods for instance lithium(Li) and sodium(Na) are alkaline metals and so belong to the same group (that is group 1).Also Hydrogen(H) and Helium(He) both have only one shell or energy level and so belong to the same period.
Answer:
I think it is a or c hope this helps
<u>Answer</u>
1.667 m/s²
Using the Newton's second law of motion;
force is directly proportional to the rate of change of momentum and it takes place in the direction of force.
i.e F = change in momentum
F = (mv - mu)/t
=m(v-u)/t
= ma
∴ F =ma
a = F/m
= 150/90
= 1.667 m/s²
The amount of energy needed to increase the temperature of a substance by
is given by
where
m is the mass of the substance
is its specific heat capacity
is the increase in temperature
The water volume is
, since its density is
, the mass of this sample of water is
The water specific heat capacity is
and the increase in temperature is
Therefore, the amount of energy needed is
Answer:
I₂ = 8 mG
Explanation:
The intensity of a beam is
I = P / A
Where P is the emitted power which is 3) 3
Let's use index 1 for the initial position of r₁ = 6 ft and 2 for the second position r₂ = 3 ft
I₁ A₁ = I₂ A₂
I₂ = I₁ A₁ / A₂
The area of the beam if we assume that it is distributed either in the form of a sphere is
A₁ = 4π r²
We substitute
I₂ = I₁ (r₁ / r₂)²
I₂ = 2 (6/3)²
I₂ = 2 4
I₂ = 8 mG
