Answer: B) Charcoal Explanation: It is Charcoal which is black when we buy it or when not being used. It gets red in appearance when put in use means to say when burning. And eventually when it's been consumed by fire or after getting burned out or used up, changes into ashes which look grey in color.

Answer: A) Air Explanation: Light travels fastest in Vacuum. The fastest thing in the whole universe is the speed of light in a vacuum like outer space. It is about 2.99 x 108 m/s.

Answer: B) 138 Explanation: The gram formula mass of a compound is nothing but the molar mass. The molar mass of K2CO3 (Potassium Carbonate) is given by Atomic weights of individual elements are   K (Potassium) = 39 g C (Carbon) = 12 g O (Oxygen) = 16 g   Hence, that of K2CO3 = 39(2) + 12 + 16(3) = 78 + 12 + 48 = 138.

Answer: C) 12.5 cm Explanation: Let the required height of the building be x meter More shadow length, More height(direct proportion) Hence we can write as (shadow length) 40.25 : 28.75 :: 17.5 : x⇒ 40.25 × x = 28.75 × 17.5⇒ x = 28.75 × 17.5/40.25= 2875 × 175/40250= 2875 × 7/1610= 2875/230= 575/46= 12.5 cm

Answer: A) General Data Protection Regulation Explanation: GDPR stands for the General Data Protection Regulation. The GDPR is a piece of EU legislation passed by the European Parliament in 2016.   It aims to make it simpler for people to control how companies use their personal details. Companies will not be allowed to collect and use personal information without the person's consent. Data includes things like a person's name, email address and phone number, and also internet browsing habits collected by website cookies.

Answer: B) Rs. 3 Explanation: Let wholesaler dealers marked price = 100%, Retailer's C.P = 80% And the retailer sells at 5% less than the marked price => S.P = 95%If S.P of 95% of the retailer costs Rs.19 to customer,so its C.P of 80% will cost 80 x 19/95 = 16 Profit made by the retailer = 19-16 =  Rs.3

A Temper.

Resistivity : Resistivity is a measure of the resistance to the flow of electrons.  Conductivity : Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.   Example: Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance.