Such a coil. will create a magnetic ï¬eld perpendicular to the magnetic needle. The ï¬eld changes direction in synchrony with the oscillation of the alternating current, so if. the frequency of the current is adjusted to the resonance frequency of the magnetic needle, the. current will set the needle in motion.
A complex number whose real part is zero is said to be purely imaginary, whereas a complex number whose imaginary part is zero is a real number. In this way, the complex numbers contain the ordinary real numbers while extending them in order to solve problems that cannot be solved with real numbers alone.
Zero is the integer denoted 0 that, when used as a counting number, means that no objects are present. It is the only integer (and, in fact, the only real number) that is neither negative nor positive. A number which is not zero is said to be nonzero. A root of a function is also sometimes known as a zero of ..