Mars has approximately half of the earth's diameter. When it is closest to the earth it is at abot 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.

The earth- moon distance is about 60 earth radius. Moon is seen to be of (1//2)^@ diameter from the earth. What must be the relative size compared to the earth?

Fig.2.49 shows a solid glass sphere of radius 5 cm that has a small air bubble O trapped at a distance 2 cm from the centre C.Th refractive index of the material of glass is 1.5.Find the apparent position of the bubble where it will appear ,when seen throught the surface from an ougtside point E. .

The earth has a radius of 6400 km . The inner core of 1000km radius is solid. Outside it, there is a region from 1000 km to a radius of 3500 km which is in molten state. Then again from 3500 km to 6400 km the earth is solid.Only longitudinal (P) waves can travel inside a liquid. Assume that the P wave has a speed of 8km s^(-1) in solid parts and of 5 km s^(-1) in liquid parts of the earth. An earthquake occur at some place closer to the surface of the earth.CAlculate the time after which it will be recorded in a seismometer at a diametrically opposite point on the earth if wave travels along diameter?

The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?

A short bar magnet of magnetic movement 5.25 xx 10^-2 J T^1 is placed with its axis perpendicular to the earth’s field direction. At what distance from the centre of the magnet, the resultant field is inclined at 45^@ with earth’s field on its axis. Magnitude of the earth’s field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.

A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the axis of the magnet at 14 cm from the centre of the magnet. The earth’s magnetic field at the place is 0.36 G and the angle of dip is zero. What is the total magnetic field on the normal bisector of the magnet at the same distance as the null-point (i.e., 14 cm) from the centre of the magnet? (At null points, field due to a magnet is equal and opposite to the horizontal component of earth’s magnetic field.)

When a body slides down from rest along a smooth inclined plane making anangle of 45^@ with the horizontal, it takes time T. when the same body slides down from rest along a rough inclined plane making the same angle and through the same distance, it is seen to take time pT, where p is some number greater than 1. Calculate the co-efficient of friction between the body and the rough plane.

The earth- moon distance is about 60 earth radius. Moon is seen to be of (1//2)^@ diameter from the earth. From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun earth diameters.

The escape speed of a projectile on the earth’s surface is 11.2 km s^-1 . A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.

A short bar magnet of magnetic movement 5.25 xx 10^-2 J T^-1 is placed with its axis perpendicular to the earth’s field direction. At what distance from the centre of the magnet, the resultant field is inclinedat 45^@ with earth’s field on its normal bisector. Magnitude of the earth’s field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.