List of top Questions asked in GATE ES

Clean water is passed through a bed of uniform spherical sand at a filtration velocity of 0.002 m/s. Sand grains are 0.4 mm diameter, specific gravity 2.65, bed depth = 0.67 m, porosity $\eta = 0.35$. Water density = 998.2 kg/m$^3$, viscosity = $1.002\times10^{-3$ Pa·s. Friction factor: \[ f = 1.75 + \frac{150(1-\eta)}{Re}, \] where $Re$ is Reynolds number. The headloss (in m, rounded off to three decimal places) using the Carman–Kozeny equation is __________.}
According to the National Ambient Air Quality Standards (CPCB, Govt. of India, 2009), which of the following statement(s) is/are correct?
Consider the figure shown below for three different cases. Which of the following statement(s) is/are correct for surface level emissions, given the environmental temperature?
As per the Solid Waste Management Rules of 2016 (Govt. of India), which of the following statement(s) is/are correct?
Carbon cycle, nitrogen cycle and phosphorus cycle play important roles in ecosystems. Which of the following statement(s) is/are NOT correct about the phosphorus cycle?
Which of the following statement(s) is/are correct regarding National Green Tribunal (NGT) of India?
An individual has four different email accounts. 60% of emails come into his corporate account,
30% come into his gmail account and the remaining 10% are equally divided into his yahoo and zoho accounts.
Only 1% of the emails in his corporate accounts are spam, whereas corresponding percentages for gmail, yahoo
and zoho accounts are 2%, 3% and 3%, respectively. Assuming that the same spam filter is used in all the four
email accounts, the probability (in percentage, rounded off to one decimal place) of having a randomly selected
email as spam is ____________.
A bag filter is used for removal of particulate matter having a range of sizes. The correct sequence of air filtration mechanisms for their removal, in order of decreasing size, is
A relatively calm room has background sound power level (SPL) of 30 decibels (dB). A television and a radio with SPL of 80 dB and 70 dB, respectively, started operating simultaneously in this room. Given the reference sound power is $10^{-12}$ Watts, what will be the resulting SPL in the room, assuming all the sources operate independently?
During night, in troposphere, which of the following is/are NOT correct?
A typical plasmid-free bacterial cell having a single chromosome consists of $\sim 55%$ protein, $\sim 3%$ DNA and $\sim 21%$ RNA (percent of dry weight). Assuming there are 2500 different types of protein molecules (with at least one copy number) being expressed in a bacterial cell at any given time, which of the following statements is/are NOT correct with respect to the number of intracellular DNA, RNA and protein molecules?
Which of the following statement(s) is/are NOT correct while comparing continuously stirred tank reactor (CSTR) and plug flow reactor (PFR)?
\[ \lim_{x\to 0} \frac{\sqrt{1+x}-1}{x} \] is ____________ (rounded off to one decimal place).
The following figure shows a 2-hour unit hydrograph (1 cm rainfall excess) for a catchment area of 540 hectare. Find the peak discharge (in m$^3$/s, rounded to one decimal place).
Eigenvalues of the matrix $\begin{bmatrix}0 & 1 \\ -2 & 3 \end{bmatrix}$ are
For an exponentially growing microbial culture, the specific growth rate $(\mu)$ is related to its doubling time $(t_d)$ by which one of the following relations?
A microbial culture with a specific growth rate of $\mu_1$ (per hour) is being grown in a continuous reactor at steady state with hydraulic retention time (HRT) of 24 hours. The reactor is subjected to a perturbation by reducing the HRT to 12 hours. The reactor recovers and comes to a new steady state with a specific growth rate of $\mu_2$. Which one of the following statements is correct?
Which one of the following statements is NOT correct with respect to a batch reactor?
If $G$ represents Gibbs free energy, select the correct statement(s).
For effluents generated by a molasses-based distillery and wood-based pulp and paper industry, which of the following statement(s) is/are NOT correct?
PM$_{2.5}$ concentrations in ambient air can be measured using
Biodegradable wastes like vegetable peelings from kitchen are usually processed by composting techniques. Which of the following option(s) regarding the processing of biodegradable wastes is/are correct?
As per ‘Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016’ of Govt. of India, the import of hazardous and other wastes from any country shall NOT be permitted for which of the following option(s)?
The Ministry of Environment, Forest and Climate Change (MoEF & CC), Govt. of India has published the Environment Impact Assessment (EIA) draft Notification 2020, intended to replace the existing EIA Notification 2006 under the Environment (Protection) Act, 1986. Which of the following is/are the key change(s) from existing regulation?
A river water sample has pH of 4 and suspended solids concentration of 100 mg/L. If alum is chosen as a coagulant, what will be the coagulation mechanism?