The magnetic field lines inside a current carrying long solenoid are in the form of

A-ray of light travelling from a rarer medium to a denser medium

An athlete completes one round of a circular track of diameter $100 \mathrm{m} \mathrm{in} 20 \mathrm{s}$. What will be the displacements after $1$ minute and $10$ s, respectively?

Which of the following statements about the universal indicators is/are true?

1. It is a mixture of several indicators.
2. It shows different colours at different concentrations of hydrogen ions in the solution.
3. It helps to determine the strength of the given acid and base in titration.

Select the correct answer using the code given below :
 

Which of the following carbon allotropes is/are good conductor(s) of electricity?

1. Diamond
2. Graphite
3. Fullerene

Select the correct answer using the code given below :