Correct Answer: C. should have stepped down

Explanation

(a)

1.Earth's rotation is the rotation of planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.

2.ForEarth to make one completerevolution around the Sun takes 365.24 days. This amount of time is the definition of one year. The gravitational pull of the Sun keepsEarth and the other planets in orbit around the star.

3.An equinox is commonly regarded as the instant of time when the plane of Earth's equator passes through the geometric center of the Sun's disk. This occurs twice each year, around 20 March and 23 September. In other words, it is the moment at which the center of the visible Sun is directly above the equator.

(b)Effects ofEarth's revolution include the seasons and variation in the length of days and nights. In addition torevolution, the tilt ofEarth's axis relative to its plane of orbit has a profoundeffect onEarth. At almost any given time, one hemisphere is tilted toward the sun, as the other is tilted away.

Explanation

(a) Area of the shaded segment = area of sector XOY - area of triangle OXY.

\(\implies 504 = \frac{\theta}{360°} \times \pi r^{2} - \frac{1}{2} r^{2} \sin \theta\)

\(\implies 504 = \frac{90}{360} \times \frac{22}{7} \times r^{2} - \frac{1}{2} \times r^{2} \sin 90\)

\(504 = r^{2}(\frac{22}{28} - \frac{1}{2})\)

\(504 = \frac{2r^{2}}{7} \implies r^{2} = \frac{504 \times 7}{2} = 1764\)

\(r = \sqrt{1764} = 42 cm\).

(b) In the diagram, \(a_{1} = a_{2}\) (base angles of an isosceles triangle)

\(\therefore a_{1} + a_{2} = 2a_{1}\)

\(\therefore 2a_{1} + 109° = 180° \implies 2a_{1} = 180° - 109° = 71°\)

\(a_{1} = a_{2} = \frac{71°}{2} = 35.5°\)

Hence, \(< RQS = 66° + 35.5°\)

= \(101.5°\)

Correct Answer: C. $18.00

Correct Answer: B. 1.2cm

Explanation

let the chord be AB = 7cm

radius OA = 3.7cm distance of the = OM using Pythagoras theorem

OA² = AM² + OM²

3.7² = 3.5² + OM²

13.69 = 12.25 + OM²

13.69 - 12.25 = OM²

1.44 = OM²

OM = \(\sqrt{1.44}\)

OM = 1.2cm

distance of chord = 1.2cm

Correct Answer: C. Increase in profit

Correct Answer: B. has lower specific heat capacity

Explanation

Specific Heat Capacity of mercury and water are 0.14 Jg\(^{-1}\)C\(^{-1}\) and 4.186Jg\(^{-1}\)C\(^{-1}\) respectively.

Correct Answer: D. wit

Correct Answer: C. Mass per unit length of string, tension in string and length of string

Explanation

The fundamental frequency of vibrations of a string is inversely proportional to the square root of mass per unit length (linear density), if the tension and vibrating length of the string are constant.

Correct Answer: D. tendency to become joint-stock compsnies