Physics
Isotopes of an element contain

the same number of protons but different number of neutrons
equal number of nucleons
equal number of protons and electrons
the same number of neutrons but different number of protons

ANSWER DOWNLOAD EXAMIANS APP

Physics
In a railway track, two rails are joined end to end with a gap in between them because

Steel can be saved
Accidents due to expansion in summer can be avoided
Air-gaps are necessary for bearing the weight of running train
Accidents due to contraction in winter can be avoided

ANSWER DOWNLOAD EXAMIANS APP