Olympiad Test: High Order Thinking Skills (HOTs)- 3 - Class 8 MCQ

Time period of the pendulum = Time taken in one complete cycle (P → Q → P) = 0.8 + 0.8 = 1.6 s. Time taken to make 14 oscillations = 14 × 1.6 = 22.4 s

In option A, effective resistance = 1 Ω, as both 2 Ω resistances are in parallel. In option B, effective resistance = 2 Ω, as switches S1 and S2 are open. In option C, effective resistance = 1 Ω + 1 Ω = 2 Ω. In option D, effective resistance = 1 Ω + 2 Ω = 3 Ω, as both resistances 1 Ω and 2 Ω are in series.

Time period of pendulum X = 15/30 = 0.5 sec. Time period of pendulum Y = 9/19 = 0.47 sec.

Temperature is highest in the outermost zone of the candle flame, i.e., figure I. Middle zone of the candle flame has unburnt carbon particles, thus a circular dark ring is formed on the slide by the deposition of unburnt carbon particles present in this zone of the candle flame (figure II). The dark zone is the zone near the wick of the candle. The (innermost) dark zone (figure III) consists of unburnt wax vapours. In figure III, these vapours rise up the glass tube and burst into flame when a lighted matchstick is brought near them. Thus, figure I represents the outermost zone or non-luminous zone. Figure II represents the luminous zone of unburnt carbon particles or middle zone of incomplete combustion. Figure III represents the innermost or dark zone of the candle flame.

The method of irrigation shown in the given figure is 'rahat'. It is a traditional method of irrigation that is based on the lever system. Drip irrigation is a modern method that delivers water drop by drop at the base of each plant and is used in places where there is a shortage of water.

P- Passenger pigeon, Q - Lion-tailed macaque, R - Bornean orangutan, S - Eastern black rhino