Frequency= velocity of light/wave length
Fr= 3×10^8/510×10^-9
Frequwency=5.88×10^14 Hz
Answer:
Given:
Radius of curvature (R) of a spherical mirror = 20
To Find:
Focal length (f)
Explanation:
Formula:
Substituting value of R in the equation:
Answer:
The answer is D.
Explanation: The northern hemisphere is more cooler, because it doesn't have much sunlight to warm it up.
Answer:
Explanation:
24 - gauge wire , diameter = .51 mm .
Resistivity of copper ρ = 1.72 x 10⁻⁸ ohm-m
R = ρ l / s
1.72x 10⁻⁸ / [3.14 x( .51/2)² x 10⁻⁶ ]
= 8.42 x 10⁻² ohm
= .084 ohm
B ) Current required through this wire
= 12 / .084 A
= 142.85 A
C )
Let required length be l
resistance = .084 l
2 = 12 / .084 l
l = 12 / (2 x .084)
= 71.42 m
