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प्रश्न
Pyrolusite ore is _______.
विकल्प
MnO
MnO2
Mn2O7
Mn2O3
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उत्तर
Pyrolusite ore is MnO2.
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संबंधित प्रश्न
Iron (z=26) is highly ferromagnetic. Explain.
What type of magnetism is shown by a substance if magnetic moments of domains are arranged in same direction?
Write the type of magnetism observed when the magnetic moments are oppositely aligned and cancel out each other.
Write the type of magnetism observed when the magnetic moments are aligned in parallel and anti-parallel directions in unequal numbers.
Explain the following with suitable examples:
Paramagnetism
Explain the following with suitable examples:
Antiferromagnetism
Explain why:
(i) Transition elements form coloured compounds.
(ii) Interhalogen compounds are more reactive than their constituent elements.
(iii) Cu+ is diamagnetic but Cu2+ is paramagnetic. (Z = 29)
Out of [CoF6]3- and [Co(en)3]3+, which one complex is
(i) paramagnetic
(ii) more stable
(iii) inner orbital complex and
(iv) high spin complex
(Atomic no. of Co = 27)
The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenonid to demagnetize the ferromagnet completely is

What is magnetic susceptibility?
What happens to the domains in a ferromagnetic material in the presence of external magnetic field?
Compare the properties of soft and hard ferromagnetic materials.
Substances which are weakly repelled in magnetic field are known as ____________.
Which of the following arrangements shows schematic alignment of magnetic moments of antiferromagnetic substances?
A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field becuase ______.
The value of magnetic moment is zero in the case of antiferromagnetic substances because the domains:
(i) get oriented in the direction of the applied magnetic field.
(ii) get oriented opposite to the direction of the applied magnetic field.
(iii) are oppositely oriented with respect to each other without the application of magnetic field.
(iv) cancel out each other’s magnetic moment.
Which one of the following homo-diatomic molecule is paramagnetic?
The heat of combustion of a substance is:
Some of the polar crystals when heated produces small electrical current. This phenomenon is called ______.
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required ?
The value of aluminium susceptibility is 2.2 × 10-5. The percentage increase in the magnetic field if space within a current carrying toroid is filled with aluminium is `"x"/10^4`. Then the value of x is ______.
Match items of List - I with those of List - II:
| List - I | List - II | ||
| (Property) | (Example) | ||
| (A) | Diamagnetism | (i) | MnO |
| (B) | Ferrimagnetism | (ii) | O2 |
| (C) | Paramagnetism | (iii) | NaCl |
| (D) | Antiferromagnetism | (iv) | Fe3O4 |
Choose the most appropriate answer from the options given below:
Give a reason for the following:
Cu+2 salts are paramagnetic, while Cu+ salts are diamagnetic.
The metal complex ion that is paramagnetic is ______.
(Atomic number of Fe = 26, Cu = 29, Co = 27 and Ni = 28)
The calculated spin only magnetic moment of Cr2+ ion is ______.
