JEE Main 2020 (Online) 2nd September Morning Slot | Magnetics Question 154 | Physics

JEE Main 2020 (Online) 2nd September Morning Slot

MCQ (Single Correct Answer)

-1

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?

T : Large retentivity, small coercivity

P : Large retentivity, large coercivity

P : Small retentivity, large coercivity

T : Large retentivity, large coercivity

JEE Main 2020 (Online) 2nd September Morning Slot

MCQ (Single Correct Answer)

-1

A beam of protons with speed 4 × 10⁵ ms^–1 enters a uniform magnetic field of 0.3 T at an angle of 60° to the magnetic field. The pitch of the resulting helical path of protons is close to :
(Mass of the proton = 1.67 $$ \times $$ 10^–27 kg, charge
of the proton = 1.69 $$ \times $$ 10^–19 C)

2 cm

12 cm

5 cm

4 cm

JEE Main 2020 (Online) 9th January Evening Slot

MCQ (Single Correct Answer)

-1

An electron gun is placed inside a long solenoid of radius R on its axis. The solenoid has n turns/length and carries a current I. The electron gun shoots an electron along the radius of the solenoid with speed v. If the electron does not hit the surface of the solenoid, maximum possible value of v is (all symbols have their standard meaning) : JEE Main 2020 (Online) 9th January Evening Slot Physics - Magnetics Question 159 English

JEE Main 2020 (Online) 9th January Evening Slot Physics - Magnetics Question 159 English

$${{e{\mu _0}nIR} \over {4m}}$$

$${{e{\mu _0}nIR} \over m}$$

$${{e{\mu _0}nIR} \over {2m}}$$

$${{2e{\mu _0}nIR} \over m}$$

JEE Main 2020 (Online) 9th January Evening Slot

MCQ (Single Correct Answer)

-1

A plane electromagnetic wave is propagating along the direction $${{\widehat i + \widehat j} \over {\sqrt 2 }}$$ , with its polarization along the direction $$\widehat k$$ . The correct form of the magnetic field of the wave would be (here B₀ is an appropriate constant) :

$${B_0}{{\widehat i - \widehat j} \over {\sqrt 2 }}\cos \left( {\omega t - k{{\widehat i + \widehat j} \over {\sqrt 2 }}} \right)$$

$${B_0}{{\widehat i + \widehat j} \over {\sqrt 2 }}\cos \left( {\omega t - k{{\widehat i + \widehat j} \over {\sqrt 2 }}} \right)$$

$${B_0}{{\widehat j - \widehat i} \over {\sqrt 2 }}\cos \left( {\omega t + k{{\widehat i + \widehat j} \over {\sqrt 2 }}} \right)$$

$${B_0}\widehat k\cos \left( {\omega t - k{{\widehat i + \widehat j} \over {\sqrt 2 }}} \right)$$

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