Physics
A step up transformer …………… the current whereas a step down transformer …………… the current.
- increases, increases
- decreases, decreases
- decreases, increases
- increases, decreases
Answer
decreases, increases
Reason — In a step up transformer the number of turns in the secondary coil is more than the number of turns in the primary coil ( Ns > Np) i.e., turns ratio n > 1. It increases the a.c. voltage and decreases the current. i.e., Es > Ep and Is < Ip.
In a step down transformer the number of turns in the secondary coil is less than the number of turns in the primary coil ( Ns < Np) i.e., turns ratio n < 1. It decreases the a.c. voltage and increases the current. i.e., Es < Ep and Is > Ip.
Related Questions
The direction of induced current is obtained by:
- Fleming's left hand rule
- Clock rule
- Right hand thumb rule
- Fleming's right hand rule
In a step up transformer:
- Ns = Np
- Ns < Np
- Ns > Np
- nothing can be said
Out of the following, which statement is incorrect ?
- The lamination of core prevents loss of energy due to eddy currents.
- The core is made of soft iron.
- A transformer can be used with d.c.
- A closed core is used so as to provide a closed path for magnetic field lines.
(a) What kind of the energy change takes place when a magnet is moved towards a coil having a galvanometer between it's ends?
(b) Name the phenomenon.