SSC JE Electrical 2019 with solution SET-2
While estimating domestic wiring cost, if the length of the PVC conduit required is 62 meters, then what is the length of the cable required?
The size of the conduit is 62 meters. In conduit, there is a 2-phase wire and 1 neutral wire. Therefore the total number of conducting wire is 3 in a conduit Total length of cable = 62 × 3 = 186 meters.
Skin Effect The steady direct current distributes itself uniformly over the whole section of a conductor but the alternating current does not distribute uniformly rather than it tends to concentrate near the surface of a conductor. In fact in the AC system, no current flows through the core and the entire current is concentric at the surface regions. This phenomenon is called skin effect. The skin effect causes the effective resistance of the conductor to increase with the frequency of the current. The skin effect is due to eddy currents set up by the AC current. The skin effect has practical consequences in the design of radiofrequency and microwave circuits and to some extent in AC electrical power transmission and distribution systems.
Indian Electricity Rules specify that the maximum load on a light/fan sub-circuit should not exceed 800 watts and the number of points should be limited to 10. Hence for light load number of sub-circuit = 3000/800 = 3.75 = 4 Indian Electricity Rules specify that the maximum load on a power sub-circuit should not exceed 3000 watts and the number of outlets should be limited to two. For the power sub-circuit load number of sub-circuit = 6000/3000 = 2 Total subcircuit = 4 + 2 = 6
In the PMMC type instrument, the deflection is directly proportional to the current flowing through the instrument, we get a uniform scale for the instrument. It gives a uniform scale of upto 270° or more. Td ∝ I