Answer:
254 °C
Explanation:
The average kinetic energy of gas molecules K = 3RT/2N where R = gas constant = 8.314 J/mol-K, N = avogadro's constant = 6.022 × 10²³ atoms/mol
T = temperature in Kelvin.
Let K be its average kinetic energy at t = -19°C = 273 + (-19) = 273 - 19 = 254 K = T. K = 3RT/2N = 3 × 8.314 J/mol-K × 254 K/(2 × 6.022 × 10²³ atoms/mol) = 5.26 × 10⁻²¹ J
When its average kinetic energy doubles, it becomes K₁ = 2K = 2 × 5.26 × 10⁻²¹ = 10.52 × 10⁻²¹ J at temperature T₂. So,
K₁ = 3RT₁/2N
T₁ = 2NK₁/3R
T₁ = 2 × 6.022 × 10²³ atoms/mol × 10.52 × 10⁻²¹ J/3 × 8.314 J/mol-K = 508 K
The temperature difference is thus ΔT = T₁ - T = 508 K - 254 K = 254 K.
Since temperature change in kelvin scale equals temperature change in Celsius scale ΔT = 254 °C
So, we need to change the temperature of the air by 254 °C to double its average kinetic energy.
As per the question the distance of venus from sun is given as 0.723 AU
We have been asked to calculate the time period of the planet venus.
As per kepler's laws of planetary motion the square of time period of planet is directly proportional to the cube of semi major axis. mathematically

⇒
where is k is the proportionality constant
We may solve this problem by comparing with the time period of the earth . We know that time period of earth is 365.5 days
Hence
The distance of sun from earth is taken as 1 AU i.e the mean distance of earth from sun
Hence 
The distance of venus from sun is 0.723 AU i.e
From keplers law we know that-
⇒
Putting the values mentioned above we get-

⇒
⇒
Hence the time period of venus is 224.388352752710 days
The image distance is 59.2 cm and the image is real and small.
<h3>
Image distance</h3>
The distance of the image formed by the convex or converging lens is determined by applying the following lens equation.
1/f = 1/u + 1/v
where;
- f is the focal length = 34 cm
- u is the object distance = 80 cm
- v is the image distance = ?
1/v = 1/f - 1/u
1/v = 1/34 - 1/80
1/v = 0.0294 - 0.0125
1/v = 0.0169
v = 1/0.0169
v = 59.2 cm
Thus, the image distance is 59.2 cm and the image is real and small.
Learn more about convex lens here: brainly.com/question/10153605
They both have a mechanical advantage meaning that the force applied to the mechanism is not the same as the force produced.