Multiplication & Division of Errors

Q. The diagram below in Fig., shows the arrangement of five different resistances connected to a battery of e.m.f. 1.8 V. Calculate :
(a) The total resistance of the circuit.
(b) The reading of ammeter A.

Q. An object O is placed at 8cm in front of a glass slab, whose one face is silvered as shown in Figure. The thickness of the slab is 6cm. If the image formed 10 cm behind the silvered face, find the refractive index of glass

Q. What is the minimum resistance which can be made using five resistors each of $\frac{1}{5}\Omega$?

1. $\frac{1}{5}\Omega$
2. $\frac{1}{25}\Omega$
3. $\frac{1}{10}\Omega$
4. $25\Omega$