1
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
At time t = 0, a material is composed of two radioactive atoms A and B, where NA(0) = 2NB(0). The decay constant of both kind of radioactive atoms is $$\lambda$$. However, A disintegrates to B and B disintegrates to C. Which of the following figures represents the evolution of NB(t) / NB(0) with respect to time t?

[NA (0) = No. of A atoms at t = 0

NB (0) = No. of B atoms at t = 0]
A
JEE Main 2021 (Online) 26th August Evening Shift Physics - Atoms and Nuclei Question 106 English Option 1
B
JEE Main 2021 (Online) 26th August Evening Shift Physics - Atoms and Nuclei Question 106 English Option 2
C
JEE Main 2021 (Online) 26th August Evening Shift Physics - Atoms and Nuclei Question 106 English Option 3
D
JEE Main 2021 (Online) 26th August Evening Shift Physics - Atoms and Nuclei Question 106 English Option 4
2
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
A transmitting antenna at top of a tower has a height of 50 m and the height of receiving antenna is 80 m. What is range of communication for Line of Sight (LoS) mode?

[use radius of earth = 6400 km]
A
45.5 km
B
80.2 km
C
144.1 km
D
57.28 km
3
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
A refrigerator consumes an average 35W power to operate between temperature $$-$$10$$^\circ$$C to 25$$^\circ$$C. If there is no loss of energy then how much average heat per second does it transfer?
A
263 J/s
B
298 J/s
C
350 J/s
D
35 J/s
4
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
An electric bulb of 500 watt at 100 volt is used in a circuit having a 200 V supply. Calculate the resistance R to be connected in series with the bulb so that the power delivered by the bulb is 500 W.
A
20 $$\Omega$$
B
30 $$\Omega$$
C
5 $$\Omega$$
D
10 $$\Omega$$
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