National Science Olympiad Forum By SOF Olympiad Trainer - Page 13
  1. Home
  2. /  Forum

User Forum

Ask Your Question
Nupur Sangwai from Podar International Parbhani, JINTUR
Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Admin from revisewise, Noida
Class : Class 1
Here, the answer is D. Black residue is obtained in test tubes I and III i.e., iron gets displaced in test tubes I and III. Therefore, metals P and R should be more reactive than iron. No change is observed in test tubes II and IV hence, metals Q and S should be less reactive than iron.

Ans 2:

Anvesha Dubey from Lodha World School , Dombivali
Class : Class 5
Since the residue obtained was black in colour and we know that only Zinc and Copper on reacting with Iron give a black residue hence the answer is Option D

Post Your Answer

Gireesha from innocent hearts school jalandhar, Jalandhar
Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Admin from revisewise, Noida
Class : Class 1
Here, the answer is D. The method used to extract metals from the ore in which they are found depends on their reactivity. For example, reactive metals such as aluminium are extracted by electrolysis, while a less-reactive metal such as iron may be extracted by reduction with carbon or carbon monoxide. The metals low in the reactive series are very less reactive. The oxides of such metals can be reduced to metals by heating alone e.g. mercury is obtained from its ore, cinnabar (HgS), by the process of heating. Metals like iron, zinc, lead etc. occur as sulphides or carbonates in nature. First the ore is converted into its oxide form This is done by either roasting or by calcination. The metal oxide is reduced to metal by using suitable reducing agent such as Carbon.

Ans 2:

Anvesha Dubey from Lodha World School , Dombivali
Class : Class 5
Option D

Post Your Answer

Gireesha from innocent hearts school jalandhar, Jalandhar
Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Admin from revisewise, Noida
Class : Class 1
Here, the answer is (d). The right hand rule can be used to determine the direction of the force on a current-carrying wire placed in an external magnetic field.

Post Your Answer

Bhavana Goswami from South City International, Kolkata
Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Admin from revisewise, Noida
Class : Class 1
Here, the correct answer is A. In (A), the incident rays are diverged after refraction, so the lens is concave and in (B), the incident rays are converged after refraction, so the lens is convex.

Post Your Answer

Avinash Mishra from Central Hindu School, Gorakhpur
Subject :NSO    Class : Class 10

Post Your Answer

Utkarsh gupta from delhi public school, mumbai
Subject :NSO    Class : Class 10

Post Your Answer

Prachi from Carmel high school gadchiroli , Gadchiroli
Subject :NSO    Class : Class 10

Ans 1:

Abhilash from The ngp school, Coimbatore
Class : Class 10
Ans C

Ans 2:

Avinash Mishra from Central Hindu School, Gorakhpur
Class : Class 10
Ans is c

Ans 3:

Abhilash from The ngp school, Coimbatore
Class : Class 10
Ans C

Ans 4:

Rikhil Gupta from Christ Academy, Bengaluru
Class : Class 9

Post Your Answer

soham bansal from st.anslem school, alwar
Subject :NSO    Class : Class 10

Post Your Answer

Anvesh from navy Children school, mumbai
Subject :NSO    Class : Class 10

Ans 1: (Master Answer)

Admin from revisewise, Noida
Class : Class 1
The correct answer is D.

Post Your Answer

sunil from Holy Grace Academy, Thrissur
Subject :NSO    Class : Class 10

Ans 1:

pranav prasoon from paramekkavu vidya mandir, Thrissur
Class : Class 10
because there is not much fissionalble material as they are mainly constituted by hydrogen

Ans 2:

pranav prasoon from paramekkavu vidya mandir, Thrissur
Class : Class 10
because there is not much fissionalble material as they are mainly constituted by hydrogen

Post Your Answer