Machine Design
A bolt of M 24 × 2 means that

The pitch of the thread is 24 mm and depth is 2 mm
Cross-sectional area of the threads is 24 mm²
The effective diameter of bolt is 24 mm and there are 2 threads per cm
The nominal diameter of bolt is 24 mm and pitch is 2 mm

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
Spring index is

Indication of quality of spring
Ratio of coil diameter to wire diameter
Load required to produce unit deflection
Its capability of storing energy

ANSWER DOWNLOAD EXAMIANS APP