Find the value of

 sin⁴30⁰ + cos⁴30⁰ – sin25⁰cos65⁰-sin65⁰cos25⁰

Richter scale is used to measure the magnitude of ___________.

 The errors that can be pointed out by the compiler are: 

Amphoteric oxide is-

What is the constant of proportionality of an oscillator if the damping force is directly proportional to the velocity

Read the given passage and answer the questions that follow

As the Sun inches closer to its peak activity in its solar cycle, an explosion has been picked up behind the north-eastern limb of the star in our solar system. Solar observatories saw bits and pieces of the explosion, which remain obscured in view from Earth's orbit. The explosion was spotted on 31 July at around 2309 UT and Earth-orbiting satellites registered a long-lasting C9.3-class solar flare. "The intensity is probably an underestimate because it was partially eclipsed by the edge of the sun. Nasa's Solar Dynamics Observatory (SDO) saw hot debris flying away from the blast site," space weather, which tracks the solar activity, reported.

While the explosion was powerful, experts have predicted that Earth is not in the line of fire from the Sun. Scientists are expected to get a view of the active region later this week as it comes to sight. Earth is not in the line of fire. The explosion is significant because it may herald an active region set to emerge over the sun's north-eastern limb later this week. A new sunspot group could bring an end to weeks of relative quiet," space weather said in its report

Select the most appropriate synonym of the given word from the passage.

Peak

Select the correct direct form of the given sentence.
He said that something might be missing in there.

At what rate per cent per annum will a sum of money double in 8 years?