The length of different internodes in a culm of sugarcane is variable because of

Two magnets are held together in a vibration magnetometer and are allowed to oscillate in the earth's magnetic field. With like poles together,$12$ oscillations per minute are made,but for unlike poles together,only $4$ oscillations per minute are executed. The ratio of their magnetic moments is:

In how many ways can a team of $10$ players be selected from $22$ players,such that $6$ particular players are always included and $4$ particular players are always excluded?

Which of the following is not correct regarding the properties of ionic compounds?

If $\operatorname{cosec} \theta = \frac{p+q}{p-q}$,then $\cot \left(\frac{\pi}{4} + \frac{\theta}{2}\right)$ is equal to

Starting from rest, the time taken by a body sliding down on a rough inclined plane at $45^{\circ}$ with the horizontal is twice the time taken to travel on a smooth plane of the same inclination and same distance. Then the coefficient of kinetic friction is: