What is the diameter of a 1.00-m length of tungsten wire whose resistance is $0.32 \Omega ?$

(a) Two microwave frequencies authorized for use in microwave ovens are: 915 and 2450 MHz. Calculate the wavelength of each. (b) Which frequency would produce smaller hot spots in foods due to interference effects?

What is the diameter of a 1.00-m length of tungsten wire whose resistance is $0.22~ \Omega?$

In lightning storms, the potential difference between the Earth and the bottom of the thunderclouds can be as high as 35,000,000 V. The bottoms of the thunderclouds are typically 1500 m above the Earth, and can have an area of $110 \mathrm{km}^{2}$. Modeling the Earth-cloud system as a huge capacitor, calculate the capacitance of the Earth-cloud system.

How much would you have to raise the temperature of a copper wire (originally at $20^{\circ} \mathrm{C}$ ) to increase its resistance by $12 \%$ ?

A bird stands on a dc electric transmission line carrying 3100 A (Fig. 25-34). The line has $2.5 \times 10^{-5} \Omega$ resistance per meter, and the bird's feet are $4.0 \mathrm{~cm}$ apart. What is the potential difference between the bird's feet?

In lightning storms, the potential difference between the Earth and the bottom of the thunderclouds can be as high as 35,000,000 V. The bottoms of the thunderclouds are typically 1500 m above the Earth, and can have an area of $110 \mathrm{km}^{2}$. Modeling the Earth-cloud system as a huge capacitor, calculate the charge stored in the "capacitor".

The rectangular block below has front-face dimensions of 10 cm by 4 cm, with a depth of 3 cm. Treat this object as an electrical resistor.

a. Rank the block based on its electrical resistance along the three illustrated coordinate directions (x, y, and z). Rank from largest to smallest.

b. If all of the dimensions of the block double (to become 20 cm wide, 8 cm tall, and 6 cm deep), what happens to the resistance along each axis?

Can a 2.5-mm-diameter copper wire have the same resistance as a tungsten wire of the same length? Give numerical details.

A 9.0-V battery is connected to a bulb whose resistance is 1.6 $\Omega$. How many electrons leave the battery per minute?

A 9.0-V battery is connected to a bulb whose resistance is $1.6 \Omega .$ How many electrons leave the battery per minute?

How much would you have to raise the temperature of a copper wire (originally at $20^{\circ} \mathrm{C}$ ) to increase its resistance by $16 \%$ ?

In lightning storms, the potential difference between the Earth and the bottom of the thunderclouds can be as high as 35,000,000 V. The bottoms of the thunderclouds are typically 1500 m above the Earth, and can have an area of $110 \mathrm{km}^{2}$. Modeling the Earth-cloud system as a huge capacitor, calculate the energy stored in the "capacitor."

Two aluminum wires have the same resistance. If one has twice the length of the other, what is the ratio of the diameter of the longer wire to the diameter of the shorter wire?