17. a
18. c
19. a
20. c
21. c
- R=ρ×L/A
ρ=R×A/L
A=pie(r²)=pie(0.6²)=pie(0.36)=1.13
ρ=2ohm×1.13mm²/1500mm
ρ=0.0015ohm.mm
2. we were told that the wires were made of the same substance so the resistivity(ρ)is the same for both wires so:
R=ρ×L/A
R=0.0015ohm.mm×500mm/0.09mm²
R=8.3'ohm
so our resistance for the second wire is :
<em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em>R</em><em>=</em><em>8</em><em>.</em><em>3</em><em>'</em><em>ohm</em>
Answer:
The correct answer to this question is D. The area of a desk top.
Explanation:
Square meters, or m^2, are the units that represent area, or the product of two lengths. This is because the length and the width both have the units meters, so when multiplied to calculate area, the resulting units are square meters or m2. Thus, the answer for this question is D.
The length of a pendulum string would be measured in meters.
The volume of an atom would be measured in m^3 (volume is the product of the length, width, and height, giving it a cubic power). However, the volume would probably be measured in a much smaller unit because atoms are very small.
The mass of a book would likely be measured in grams or kilograms.
Answer:
(F)reaction = - 75 N
where, negative sign shows opposite direction.
Explanation:
This question can be answered using Newton's third law of motion. The Newton's Third Law of Motion states that for every action force there is an equal but opposite reaction force.
(F)action = - (F)reaction
Hence, in our scenario if we consider the 75 Newton force applied on the wall to be the action force then the reaction force of the wall must be equal to it in opposite direction. Therefore, the reaction push of the wall must be equal to 75 N.
<u>(F)reaction = - 75 N</u>
<u>where, negative sign shows opposite direction.</u>
Your answer would be B, Reflected light! hope this helps
