Answer:
Explanation:
The sensor contains an LDR which has a resistance of 10kohlms in daylight and 100kohlms in the dark.
If the resistor in the circuit is 1 megaohlm, the total resistance in daylight and darkness will be 1.01 megaohms and 1.1 megaohlms.
The percentage difference = (1.1-1.01)/1.1*100% = 8.18%
If the resistor in the circuit is 25 kohlm, the total resistance in daylight and darkness will be 35 kohms and 125 kohlms.
The percentage difference = (125-35)/125*100% = 72%
With the input p.d to the sensing circuit fixed at 12 v, the sensing current will change according to the total resistance. A 72% difference is much more detectable. So the 25 kohm resistor is the better choice.
Answer:
A
Explanation:
When you pull the string the weight will experience a downward force and come closer to the vertical tube. And the angle between weight and hand through string is decreased so the angular velocity decreases
Answer:
900 m ( 0.9 km)
Explanation:
from the question we have the following
first person's height (h) = 100 m above the earths surface
distance to the horizon that can be seen (s) = 15 km = 15,000 m
second person's height (h1) = 36 m
distance to the horizon that can be seen (s1) = ?
take note that the distance (s) a person can see = square root of the person's height
s =
x K
where k is a constant
from the height and the distance the first person can see we can get the value of K
15000 =
x K
15000 = 10 x K
K = 150
now putting the value of K and the height of the second person into the equation we can get the distance into the horizon the person can see
s =
x 150
s = 900 m
therefore the second person who is 36 m above the surface can see 900 m ( 0.9 km) into the horizon
Answer:
D
Explanation:
plz plz this answer is good i hope