GATE Environmental Science Mock Test - 1 - GATE Environmental Science MCQ

Consider a square sheet of side 4 unit. The sheet is first folded along the main diagonal. This is followed by a fold along its line of symmetry. The resulting folded shape is again folded two times (one after another) along its line of symmetry.
The area of each face of the final folded shape, in square units, equal to _________

It is little realized how slowly, how painfully, we approach the expression of truth. We are so variable, so anxious to be polite, and alternately swayed by caution or anger. Our mind oscillates like a pendulum: it takes some time for it to come to rest. And then, the proper allowance and correction has to be made for our individual vibrations that prevent accuracy. Even the compass needle doesn't point the true north, but only the magnetic north. Similarly our minds at best can but indicate magnetic truth, and are distorted by many things that act as iron filings do on the compass. The necessity of holding one's job: what an iron filing that is on the compass card of a man's brain!

One of the following sentences provides support for the conclusion about "truth". Which one? 

X is normally distributed with following data (25.8, 36.6, 26.3, 21.8, 27.2). Select the correct statement about X (t_{crit, α=0.05,4} = 2.132):

Specific conductance is used in water analysis to indirectly estimate dissolved solids. The measurements used in the method accounts for

Residence time of the methane gas is approximately____

Determine the order of the reaction and the corresponding rate constant.

Which of the following type of plastic should be avoided for use in food container because it contain BPA?

Consider the following statements

Statement 1: Goodrich method for reservoir routing is based on hydrologic flood routing method.

Statement 2: Muskingum method for channel routing is based on hydraulic flood routing method.

The correct order of hydraulic conductivity for the geologic formations is 

Which of the following is NOT a goal of UN MGD's (Millennium Development Goals)?

Which of the following is a primary pollutant?

If G represents Gibbs free energy, select the correct statement(s)

PM2.5 concentrations in ambient air can be measured using

The volume of a continuous stirred tank bioreactor is 5000 liters. The feed flow rate to the reactor is 1m³/hr. And the glucose concentration in the feed is 7g/l. Determine the steady-state substrate concentration in g/l.(rounded off to one decimal places). Use the following cell constants:-umax = 0.3 per hr, Ks = 0.4g/l.

Which one of the following is the general solution of the first order differential equation dy/dx = (x + y - 1)², where x and y are real?

For an exponentially growing microbial culture, the specific growth rate (µ) is related to its doubling time (t_d) by which one of the following relations?

A microbial culture, with a specific growth rate of µ1 (per hour), is being grown in a continuous reactor at steady state with hydraulic retention time (HRT) of 24 hours. This reactor is subjected to a perturbation by reducing the HRT to 12 hours. The reactor recovers from the perturbation and comes to a new steady state with a new specific growth rate of µ₂ (per hour). Which one of the following statements is correct?

Which of the following is/are causes positive radiative forcing?

Note: This is a MSQ. One or more than one option can be correct

Which of the following statements is/are NOT correct?

Note: This is a MSQ. One or more than one option can be correct

An isolated storm of 3 hours occurred over a catchment area in the following manner 

Total rainfall excess (in cm, rounded off to one decimal place) over the catchment for the above storm is ____________. 

A sewage treatment plant with a capacity of 10 million litres per day (MLD) is treating the sewage through an aerobic biological process. The inlet and outlet BOD are measured as 100 and 30 mg/l, respectively. If the mixed microbial culture has an observed biomass yield of 0.5 g Volatile Suspended Solids (VSS)/g BOD, the sludge production rate (in kg per day, rounded off to one decimal place) when the plant is operating at 80% capacity will be _________.

A solution has 0.001 mole/L zinc ions having pH of 6. Solubility product of zinc hydroxide is given as 8×10^-18 (mole/L)³. Ignoring activity corrections, the ratio (rounded off to two decimal places) of reaction coefficient to solubility product would be ___________

The Henry’s law constant of CO₂ is 3.4×10^-2 M per atm in neutral water at 25⁰C. The dissolved CO₂ (i.e., CO₂.H₂O) at equilibrium undergoes the following reactions.
CO₂ . H₂O ⇌ H⁺ + HCO^-₃ (Equilibrium constant = 4.3 × 10^-7 M) 
HCO^-₃ ⇌ H⁺ + CO^2-₃ (Equilibrium constant = 4.7 × 10^-11 M) 
If ambient CO₂ concentration is 300 ppm, the total dissolved CO₂ (in µM, rounded off to one decimal place) is ________.

A coarse screen being used for the raw water treatment has a screen constant k = 1.43. Calculate velocity through the screen (in m/s, round up to 2 decimal places) if it is given that the velocity of approach is 3 m/s and head loss through the screen is 1.5 m.

The lengths of a large stock of titanium rods follow a normal distribution with a mean (μ) of 350 mm and a standard deviation (σ) of 1 mm. What is the percentage of rods (rounded off to the nearest integer) whose lengths lie between 349 mm and 352 mm?

The daily water requirement for a city is 100 MLD. 50 mg/L of chlorine is added to it to carry out the disinfection. If the disinfection constant is 0.25/min, the volume of the disinfection tank (in m³ , round up to 2 decimal places) required to achieve 98% degree of disinfection is ____.

The two sides of a fair coin are labelled as 0 and 1. The coin is tossed two times independently. Let P and Q denote the labels corresponding to the outcomes of those tosses. For a random variable X, defined as X = max(P,Q), the expected value E(X) (rounded off to two decimal places) is