Answer: 
Explanation:
Given
Distance between two speakers is 8 m
Man is standing 12 away from the wall
When the person moves 3 parallel to the wall
the parallel distances from the speaker become 4+3, 4-3
Now, the difference of distances from the speaker is

Condition for destructive interference is

for second destructive interference; n=2

The number of significant digits of any measurement is determined by the instrument used for such measurement. For example, in this case, we have the height of a small child being measured. We can use a simple ruler for this, and we see that a ruler has ten divisions for 1 cm. This means that the ruler cannot measure beyond the size of 0.1 cm or 1 mm. Hence, when we report the height of the small child, we report it to one significant digit after the decimal place. As an example, if we measure a child's height to be 90 full cm divisions and 8 smaller divisions, we report it as 90.8 cm but not 90.83 or 90.86 cm.
Answer:
force at the top will be 388 N which is nearly equal to 389
option (b) is correct
Explanation:
We have given velocity of the moving car v = 10 m/sec
Radius of the circular section r = 30 m
Mass of the passenger m = 60 kg
Acceleration due to gravity 
At the top normal force is given by 
So force at top will be 
So force at the top will be 388 N which is nearly equal to 389
So option (b) is correct
Acceleration is the rate of change of velocity, and velocity is the change in displacement over the change in time so the answer would be A.
Answer:
Photosynthesis occurs in the organelle, chloroplast .
Cellular respiration occurs in a plants or animals mitochondria.
Explanation:
Hope this helps! :)