Its b
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Answer:
Explanation:
As given, the student has three balloons and rubs two of them on a piece of wool. The rubbing of balloon on wool is the independent variable as it was done on two and not on the third as control.
Answer:
0.232 mm.
Explanation:
Power, P = 96 W
Voltage, V = 120 V
Length of wire, l = 4.2 m
Let r be the radius of the wire.
Resistivity of nichrome, ρ = 1.5 x 10^-6 ohm metre
P = V^2 / R
R = 120 x 120 / 96 = 150 ohm
r = 1.16 x 10^-4 m
Diameter = 2 x r = 2 x 1.16 x 10^-4 = 2.32 x 10^-4 m = 0.232 mm
Thus, the diameter of the wire is 0.232 mm.
Answer:
0.6m/s²
Explanation:
Given parameters:
Initial velocity = 3m/s
Final velocity = 4.5m/s
Time taken = 2.4s
Unknown:
Average acceleration = ?
Solution:
To solve this problem, we use the expression:
Acceleration =
v is the final velocity
u is the initial velocity
t is the time taken
Acceleration = = 0.6m/s²
Answer: option (D.)They send signals in the gigahertz range to relays in the line of sight.
Explanation:
Microwaves are a form of electromagnetic waves with wavelengths between from about a meter to a millimeter; and they possess frequencies between 300 mega hertz(MHz )and 300 giga hertz(GHz.)
Microwaves travel by line-of-sight; unlike other radio waves of lower frequency. They do not bend around hills, nor follow the earth's surface as ground waves, nor reflect from the ionosphere .Therefore land microwave communication links are restricted only tovisual horizon to about 40 miles (64 km).