Answer:
Current, I = 0.0011 A
Explanation:
It is given that,
Diameter of rod, d = 2.56 cm
Radius of rod, r = 1.28 cm = 0.0128 m
The resistivity of the pure silicon, 
Length of rod, l = 20 cm = 0.2 m
Voltage, 
The resistivity of the rod is given by :


R = 893692.30 ohms
Current flowing in the rod is calculated using Ohm's law as :
V = I R


I = 0.0011 A
So, the current flowing in the rod is 0.0011 A. Hence, this is the required solution.
If the resistor is in series with the rest of the circuit then a is the correct answer. The voltage across the resistor in series with another resistor is

where R is the big resistor and r is the small one and V is the total voltage drop across both. This is called a voltage divider
Answer:
Abby is standing (4.5^2 + 2.3^2)^1/2 from the far speaker
D2 = 5.05 m from the far speaker
The difference in distances from the speakers is
5.05 - 4.5 = .55 m (Let y be wavelength, lambda)
n y = 4.5
(n + 1) y = 5.05 for the speakers to be in phase at smallest wavelength
y = .55 m subtracting equations
f = v / y = 340 / .55 = 618 / sec should be the smallest frequency
The middle or centre of the Earth is the core. However the middle of the layers from the surface to the centre of the Earth is known as mantle.