List of practice Questions

An anaerobic digestion system is operated for methane gas generation from organic fraction of municipal solid waste (OFMSW). The moisture content and volatile solids (VS) content of OFMSW are 20% and 90%, respectively. The biodegradable volatile solids (BVS) in the VS is 70%, and the BVS conversion efficiency to methane gas is 85%.
If the methane gas generation in the system is 12 m3 per kg of BVS converted, the total volume of gas produced from one kilogram of OFMSW is ______ m3 (rounded off to two decimal places).
The characteristics of two types of solid waste are given in the table.

Type of solid wasteMoisture content (%)Nitrogen content (%)Carbon to Nitrogen (C/N) ratio
Leaves500.750
Sludge755.66.3

The quantity of sludge to be added to leaves to achieve a C/N ratio of 25 (on dry basis) for the mixed waste is ______ kg of sludge/kg of leaves (rounded off to three decimal places).
The concentration of chemical A in ambient air is 50 \(\mu g/m^3\) and the toxicological index limit for a threshold health effect for this chemical is 5 mg.

If the average breathing rate is 4 L/min, the minimum time of exposure that can lead to any health effect is ______ days (rounded off to one decimal place).
The area in the first quadrant bounded by the function \(y = (8-x)\) and the coordinate axes is ______ square units (answer in integer).
An agricultural land can support energy crops yield to produce 7000 L of bioethanol per hectare and energy content of bioethanol is 21 MJ/L. This bioethanol displaces fossil-based petrol.

The \(CO_2\) offset potential of land used for growing energy crops as a bioethanol feedstock is ______ \(\times 10^6\) g of \(CO_2\)/hectare (rounded off to one decimal place).

Consider \(CO_2\) footprints of 10 g and 80 g of \(CO_2\) per MJ for bioethanol and petrol, respectively.
At which age does a child have a vocabulary of 2000 to 2500 words?
Suresh said, "I did it yesterday." Which one of the following options is the correct form of this sentence in indirect speech?
To continue the sequence of tiles shown, the tile indicated by the question mark should be
Consider an art gallery whose walkways are shown as lines in the diagram. A black dot represents a junction of two walkways. A guard may be placed at a junction to watch over the walkways that join at that junction. The minimum number of guards needed to watch all the walkways is ________.
The 2nd of June is a Thursday in a certain year. Which day of the week is the 3rd of July in that year?
A coin with heads facing up is shown as H and a coin with tails facing up is shown as T.
Six coins are placed in the Starting Arrangement, as shown in the figure below. A "step" is defined as interchanging a pair of adjacent coins without flipping them. The minimum number of steps needed to go from the Starting Arrangement to the Final Arrangement, as shown in the figure, is ________.
Exacerbate : Mitigate :: ___________
Choose the option with the correct pair of words to fill the blank.
A paper shown in Panel I is folded along the dashed lines (- - -) to construct a cube. The shaded regions shown in Panel I appear on the outer surface of the cube. Referring to cubes shown in Panel II, which one of the options is correct?
In a population, patients who have high cholesterol also have high blood pressure (BP). Some patients with high BP also have diabetes. There are no patients who have both high cholesterol and diabetes. Furthermore,
1. the total number of patients with at least one of these conditions is 75,
2. the number of patients with high cholesterol is 10,
3. the number of patients with high BP is 45, and
4. the number of patients with only high BP and no other conditions is 20.
Then the number of patients who have both diabetes and high BP is _______
Four people P, Q, R, and S, of different ages, make the following observations.
P: I am younger than S.
Q: I am neither the youngest nor the oldest.
R: P is older than me.
Based on these observations, the youngest person is ______.
Circles \(C_1\), \(C_2\), and \(C_3\), with centers \(O_1\), \(O_2\), and \(O_3\), and radii \(r_1\), \(r_2\), and \(r_3\), respectively, touch each other as shown in the following figure. Given \(r_1 = 2\) cm, \(r_2 = 1\) cm and the angle \(\angle O_1 O_3 O_2\) is 90 degrees, \(r_3 =\) _____ cm.
Which one of the following increases over time when the soil is fully saturated?
In which one of the following layers inside the Earth, the velocity of the P-wave exceeds 13 km/s?
Which one of the following is NOT a volcanic igneous rock?
If \(r_1\) and \(r_2\), respectively, denote the equatorial and polar radii of a reference ellipsoid, then the radius, \(R\), of its equivalent sphere is given by
Which of the following sources is/are used in land seismic surveys?
A pebble has an average diameter of 8 mm. Its \(\phi\)-value on the Udden-Wentworth scale is ___________ (answer in integer).
A quartz vein in a granitic outcrop has an initial length of 20 cm. If it undergoes uniform stretching resulting in a longitudinal strain of 0.45, the length of the vein post deformation is _________cm (answer in integer).
Which one of the following is the CORRECT pair of radioactive parent isotope and the corresponding radiogenic daughter isotope?
Which one of the following pairs of geophysical signatures most commonly indicates volcanogenic massive sulphide deposits?