Two wires A and B with circular cross sections are made of the same metal and have equal lengths, but the resistance of wire A is three times greater than that of wire B. What is the ratio of the radius of A to that of B?
1.3
2.?3
3.1
4.1/?3
5.1/3
4
You might also like to view...
This visible-light photo shows a starburst galaxy. What is going on with the reddish gas that seems to be emerging on both sides of it?
A) It is gas being blown out in a galactic wind. B) It is gas from a protogalactic cloud that is still falling inward toward the galactic center. C) The gas represents jets being shot out from the region of a supermassive black hole. D) The gas consists of many individual stars that are bursting out from the central regions of the galaxy.
If you could convert the entire mass of the Sun (mass 2 x 1033g) into pure energy, how much energy would be produced (in ergs) ? The speed of light c = 3 x 1010cm/s.
A. 2 x 1033ergs B. 1.8 x 1054ergs C. 6 x 10133ergs D. 1 x 1051ergs E. 6 x 1043ergs
A hologram is simply a
A) complex diffraction grating. B) thin sheet of non-cubic transparent crystals. C) pair of semi-crossed polarization filters. D) thin photographic film with microscopic images over the entire surface. E) none of the above
On its own, a certain tow-truck has a maximum acceleration of 3.0 m/s2. What would be the maximum acceleration when this truck was towing a bus of twice its own mass?
A) 2.5 m/s2 B) 2.0 m/s2 C) 1.5 m/s2 D) 1.0 m/s2