Answer:

Explanation:
A number can be written in the form of :

Where
m is the real number
n is any integer
In this case, the average distance from the Sun to the Earth is given,
d = 150000000000 meters
There are 10 zeroes in this number. We need to write this number in scientific notation. It is given by :

So, the average distance from the Sun to the Earth is
. Hence, this is the required solution.
<span>Heating food under a heat lamp is an example of heat transfer by
<span>Radiation</span></span>
To solve this problem it is necessary to apply the concepts related to the Stefan-Boltzmann law which establishes that a black body emits thermal radiation with a total hemispheric emissive power (W / m²) proportional to the fourth power of its temperature.
Heat flow is obtained as follows:

Where,
F =View Factor
A = Cross sectional Area
Stefan-Boltzmann constant
T= Temperature
Our values are given as
D = 0.6m

The view factor between two coaxial parallel disks would be


Then the view factor between base to top surface of the cylinder becomes
. From the summation rule


Then the net rate of radiation heat transfer from the disks to the environment is calculated as





Therefore the rate heat radiation is 780.76W
Answer:
C. 441 N
Explanation:
Gravitational force between two objects can by calculated by the formula
= G m₁m₂ / r² , m₁ and m₂ are masses at distance r
= ( 6.67 x 10⁻¹¹ x 45 x 5.98 x 10²⁴) / ( 6.38 x 10⁶ )²
= 44.09 x 10
= 440.9 N
= 441 N .