List of top Surface Environment Questions

A rectangular face of 2.0 m x 2.5 m dimension is blasted with 20 kg explosive in a 1000 m long drive. One kilogram of explosive produces 2200 cm³ of nitrous fumes. The face is ventilated with a duct, located 10.0 m away from the face, to dilute the fumes. The quantity of air, in m³/s to be circulated for reducing the concentration of nitrous fumes to 5 ppm within a period of 5 minutes, is ____. (round off up to 2 decimals)
[Use the relation, t=2.303 \(\frac{V_m}{Q}\) log \(\frac{q}{v_mc}+\frac{v-v_m}{Q}\) where t=time, V_m=volume of the tunnel over which the mixing of the gases produced at the face, and air delivered by the fan occurs, c = concentration at time, t, V = volume of tunnel, Q = quantity of air flow, q = total volume of nitrous fumes produced]

Polluted air with particulate matters of diameter 50 μm enter with a horizontal velocity of 1.0 m/s at a height of 0.5 m from the bottom of a dry settling chamber. The density of the particle is 2000 kg/m³ and dynamic viscosity of the air is 1.8×10^-5 kg/m-s.
Assume streamline flow and the density of air is negligible as compared to particles and uniform horizontal velocity of 1.0 m/s of gas and particles within the chamber. 
Considering particle settling follows Stoke's law, the minimum length in m, of the chamber required for settling of the particle at its bottom, is____.(round off up to 2 decimals)

The void ratio of an unconsolidated soil heap of volume 1000 m³ is 1.0. If the soil heap is consolidated to a volume of 800 m3, the corresponding void ratio is_____.(round off up to 2 decimals)

A coal washery discharges 300 m³/day of contaminated water in a stream having a flow rate of 0.04 m³/s. The DO level of the stream and the contaminated water are 8.5 mg/L and 4 mg/L, respectively. Neglecting the impact of temperature, the resultant DO, in mg/L, of the stream just after mixing is_____.(round off up to 2 decimals)

Exposure to loud impulsive noise may lead to

A production function at time 𝑡 is given by
\(Y_t=A_tK^a_tL^{1-a}_t\) , 𝛼 ∈ (0, 1), 𝛼 ≠ 0.5, 
where 𝑌 is output, 𝐾 is capital, 𝐿 is labour and 𝐴 is the level of Total Factor Productivity. Define per capita output as \(𝑦_𝑡 ≡ \frac{𝑌_𝑡}{ 𝐿_𝑡} \)and capital-output ratio as \(𝑘_𝑡 ≡\frac{ 𝐾_𝑡}{ 𝑌_𝑡}\) . For any variable 𝑥𝑡 , denote \(\frac{𝑑𝑥_𝑡}{ 𝑑𝑡}\) by 𝑥̇ . The per capita output growth rate is