Answer:
At light intensity I = 3, is P a maximum
Explanation:
Given:

now differentiating the above equation with respect to Intensity 'I' we get

or

or

or

Now for the maxima 
thus,

or

or

or

or
I = 3
thus, <u>for the value of intensity I = 3, the P is maximum</u>
at I = 3

or

or

Answer: 0.8 m
Explanation:
Velocity of throw = 4m/s
Maximum Height attained(h) =?
Downward acceleration experienced = 10m/s^2
Using the relation:
v^2 = u^2 + 2aS
v = final Velocity = 0 (at maximum height)
u = Initial Velocity = 4
a = g downward acceleration = - 10
0 = 4^2 + 2(-10)(S)
0 = 16 - 20S
20S = 16
S = 16 / 20
S = 0.8m
Maximum Height attained = 0.8m
The volume of the block of wood is given by length × width ×height
= 2.75 × 4.80 × 7.5
= 99 cm³
Density is given by mass/volume
Thus = 84.0 g/ 99 cm³
= 0.848 g/cm³
Hence; since the block is less dense than water (1 g/cm³) it will float
Answer:
D)
Explanation:
The Period-Luminosity relationship tells us that luminosity increases with the period, and of course the more luminosity a star has the more far away they can be seen, so from this we know that:
A) False since lower luminosities can be observed when they are close.
B) False since longer periods means higher luminosities
C) False since lower luminosities can be observed when they are close.
D) True: Variable stars with shorter periods have lower luminosities, so they can only be observed when they are close.