Answer:
A₁/A₂ = 0.44
Explanation:
The emissive power of the bulb is given by the formula:
P = σεAT⁴
where,
P = Emissive Power
σ = Stefan-Boltzman constant
ε = Emissivity
A = Surface Area
T = Absolute Temperature of Surface
<u>FOR BULB 1:</u>
Since, emissivity and emissive power are constant.
Therefore,
P = σεA₁T₁⁴ ----------- equation 1
where,
A₁ = Surface Area of Bulb 1
T₁ = Temperature of Bulb 1 = 3000 k
<u>FOR BULB 2:</u>
Since, emissivity and emissive power are constant.
Therefore,
P = σεA₂T₂⁴ ----------- equation 2
where,
A₂ = Surface Area of Bulb 2
T₂ = Temperature of Bulb 1 = 2000 k
Dividing equation 1 by equation 2, we get:
P/P = σεA₁T₁⁴/σεA₂T₂⁴
1 = A₁(3000)²/A₂(2000)²
A₁/A₂ = (2000)²/(3000)²
<u>A₁/A₂ = 0.44</u>
#39. rain, snow, sleet and hail.
Answer:
<h2>90 J</h2>
Explanation:
The work done by an object can be found by using the formula
workdone = force × distance
From the question we have
workdone = 30 × 3
We have the final answer as
<h3>90 J</h3>
Hope this helps you
Answer:
C) High voltage to low voltage
Explanation:
At a power plant, there is a production of electricity at a high voltage compared to the voltage provided to our home.
Voltage of about 12 KV is produced by power plant which is then converted into about 400 KV or greater (depending upon the countries) to transfer electricity from power plant to city Grid station using Step-up transformer. At City Grid station, Step-down transformer is used to convert high voltage (about 400 KV) to low voltage (about 13 KV) to transfer electricity from grid station to the city. Then this low voltage (about 13 KV) again converted to 220 V using Step-down transformer for household usage. So, overall about 12 KV voltage at power plant is converted into 220 V for household usage using step-up and step-down transformer at different stages.
