Q.A carbon resistor of $(47 \pm 4.7)$ k$\Omega$ is to be marked with rings of different colours for its identification. The colour code sequence will be

Construction. A carbon resistor, the type used constantly in the physics laboratory, is built from a ceramic core coated with a thin layer of crystalline carbon; such resistors are prized for being inexpensive, electrically stable, and physically compact compared with wire-wound alternatives.

The colour code. Rather than printing a resistance value as text (impractical on such a small component), the value is encoded using a sequence of coloured rings painted around the resistor's cylindrical body. The first ring gives the first significant digit, and the second ring gives the second significant digit; the third ring gives the decimal (power-of-ten) multiplier that the two-digit number formed by the first two rings is multiplied by. An optional fourth ring, coloured either gold or silver, encodes the resistor's tolerance: gold means a tolerance of $\pm5\%$, and silver means $\pm10\%$; if a resistor carries no fourth ring at all, its tolerance is understood by convention to be $\pm20\%$. …