shekchand

1.Latent period - A short measurable period of apparent inactivity between the point of stimulus &  the point of skeletal muscle contraction.

2.Einthoven's triangle - The roots of both upper limbs & the left lower limb form a equilateral triangle.

3.Induction current - It is interesting to note that  current is induced in secondary coil from the primary coil during the change(i.e when current starts flowing in primary coil & again when it stops )