Answer
Verified
380.1k+ views
Hint: In order to solve this question, we need to find the emissivity of the body given. Emissivity is the measure of degree to be able to radiate energy by a body. Use this concept to find the answer to this question.
Formula used:
$E = \varepsilon Pt$where $\varepsilon = $emissivity, $P = $Power, $t = $time taken
Complete answer:
Emissivity, $\varepsilon = 1 - 0.6$ $\therefore $because it is an opaque body.
$\varepsilon = 0.4$
We have provided $P = $$20watts$, $t = 2$minutes and $\varepsilon = 0.4$
Substituting all these value in below formula we get energy:
$ E = \varepsilon Pt \\
E = 0.4 \times 20 \times 2 \times 60 \\
E = 960J \\
$(convert minutes into seconds by multiplying it by $60$)
The radiant heat energy is option(B) $960J$
Note: Points to be kept in mind while solving these questions:
Should have proper knowledge of emissivity because emissivity can be confusing sometimes.
Should learn all the important formulas as this topic contains lots of formulas which can be messy.
Formula used:
$E = \varepsilon Pt$where $\varepsilon = $emissivity, $P = $Power, $t = $time taken
Complete answer:
Emissivity, $\varepsilon = 1 - 0.6$ $\therefore $because it is an opaque body.
$\varepsilon = 0.4$
We have provided $P = $$20watts$, $t = 2$minutes and $\varepsilon = 0.4$
Substituting all these value in below formula we get energy:
$ E = \varepsilon Pt \\
E = 0.4 \times 20 \times 2 \times 60 \\
E = 960J \\
$(convert minutes into seconds by multiplying it by $60$)
The radiant heat energy is option(B) $960J$
Note: Points to be kept in mind while solving these questions:
Should have proper knowledge of emissivity because emissivity can be confusing sometimes.
Should learn all the important formulas as this topic contains lots of formulas which can be messy.
Recently Updated Pages
what is the correct chronological order of the following class 10 social science CBSE
Which of the following was not the actual cause for class 10 social science CBSE
Which of the following statements is not correct A class 10 social science CBSE
Which of the following leaders was not present in the class 10 social science CBSE
Garampani Sanctuary is located at A Diphu Assam B Gangtok class 10 social science CBSE
Which one of the following places is not covered by class 10 social science CBSE
Trending doubts
Which are the Top 10 Largest Countries of the World?
The states of India which do not have an International class 10 social science CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
How do you graph the function fx 4x class 9 maths CBSE
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE
Difference Between Plant Cell and Animal Cell
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Why is there a time difference of about 5 hours between class 10 social science CBSE
Name the three parallel ranges of the Himalayas Describe class 9 social science CBSE