Answer:
v = 2591.83 m/s
Explanation:
Given that,
The electric field is 1.27 kV/m and the magnetic field is 0.49 T. We need to find the electron's speed if the fields are perpendicular to each other. The magnetic force is balanced by the electric force such that,
So, the speed of the electron is 2591.83 m/s.
Answer:
F = 2 × 10⁻³ N
Explanation:
Given:
frequency, f = 2400 MHz
Height, h = 25cm = 0.25 m
Area of the base, A = 30 cm x 30 cm = 900 cm² = 0.09 m²
Energy of the microwave, E = 0.50 mJ = 0.5 x 10⁻³ J
Now, the time taken by the wave from top to the base, t = h/c
here, c is the speed of the light
thus,
t = 0.25/(3 x 10⁸) = 8.33 x 10⁻¹⁰ s
The radiation pressure = Intensity/c
now, the intensity is given as:
I = Power/ area
also,
Power = Energy/ time = 0.5 x 10⁻³ J/8.33 x 10⁻¹⁰ s = 600000 W
thus,
I = 600000 W/ 0.09 m² = 6666666.6 W/m²
substituting the value in the formula for pressure due to radiation, we have
= 6666666.6 W/m²/(3 x 10⁸)
also
pressure = Force/ area
thus,
Force/ area = 6666666.6 W/m²/(3 x 10⁸)
or
Force (F) = (6666666.6 W/m² × 0.09 m²)/(3 x 10⁸)
or
F = 2 × 10⁻³ N