Answer:
B= 55.6×10^(-7) Tesla
Explanation:
B= μoI/(2πr)
B: magnetic field strength
μo: permeability of free space and is equal to 4π×10^(-7) T.m/A
r: distance from the wire
I : current in the wire
B= (4π×10^(-7)×125)/(2π×4.5)
B= 55.6×10^(-7) Tesla
Answer:
Explanation:
Threshold frequency = 4.17 x 10¹⁴ Hz .
minimum energy required = hν where h is plank's constant and ν is frequency .
E = 6.6 x 10⁻³⁴ x 4.17 x 10¹⁴
= 27.52 x 10⁻²⁰ J .
wavelength of radiation falling = 245 x 10⁻⁹ m
Energy of this radiation = hc / λ
c is velocity of light and λ is wavelength of radiation .
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 245 x 10⁻⁹
= .08081 x 10⁻¹⁷ J
= 80.81 x 10⁻²⁰ J
kinetic energy of electrons ejected = energy of falling radiation - threshold energy
= 80.81 x 10⁻²⁰ - 27.52 x 10⁻²⁰
= 53.29 x 10⁻²⁰ J .
The force of gravity between the astronauts is 
Explanation:
The magnitude of the gravitational force between two objects is given by:
where
:
is the gravitational constant
are the masses of the two objects
r is the separation between them
In this problem, we have two astronauts, whose masses are:

While the separation between the astronauts is
r = 2 m
Substituting into the equation, we can find the gravitational force between the two astronauts:

Learn more about gravitational force:
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Answer:
work = 1125 [J]
Explanation:
To solve this problem we must remember the definition of power, which is defined as the relationship between work and time. The power can be calculated using the following equation:
Power = work/time
Power = 12.5 [w]
work = joules [J]
time = 1.5 [min] = 90 [s]
work = 12.5*90
work = 1125 [J]