EM-TEST-2

• The magnetic flux through a plane, denoted by Φb, is determined by the formula Φb = BAcosθ.
• In this formula, θ is the angle between the normal to the plane and the magnetic field (B).
• Given that the angle to the plane is 60^o, the angle 'θ' will be 90-60 = 30.
• Therefore, the correct answer is B, "Φb = BAcos30".

• Whether regarded from a classical perspective or the viewpoint of quantized photons, photons are not influenced by static electrical or magnetic fields.
• Photons do not possess a charge, hence, their trajectory is not altered when passing through a magnetic field.
• Consequently, the correct answer is D, "It is not deflected".

• Electrons experience force from the electric field as they move through a uniform magnetic field and an electric field.
• Although there is no magnetic force acting on the electron, its motion is slowed due to the electric field.
• As a result, the correct answer is B, "Its velocity will decrease".

• The component of velocity perpendicular to the magnetic field causes the particle to move in a circular orbit.
• Meanwhile, the component of velocity parallel to the magnetic field causes the particle to drift in that direction.
• Consequently, the particle traces an overall helical path.
• Thus, the correct answer is D, "Helical".

• Tesla (T) and Gauss (G) are both units utilized to describe magnetic induction.
• The conversion relationship is such that 1 Tesla is equal to 10,000 Gauss
• Therefore, the correct answer is D, "1T equals 10000 G (10^4 G)".

• A magnetic needle in a non-uniform magnetic field will experience different forces and torques due to the variation in the magnetic field.
• As such, both a force and a torque will act on the needle.
• Consequently, the correct answer is D, "Both a force and a torque".

• Crossing the velocity vector with the magnetic field vector gives the magnetic force on a moving charged particle.
• If the angle between the velocity vector (V) and the magnetic field (B) is zero, the magnetic force will be zero because the sine of zero is zero.
• Therefore, the correct answer is C, "Zero".

• In magnetic fields, forces are exerted on moving charged particles.
• A stationary charge, regardless of the magnetic field's strength, experiences no force as there are no moving charges to interact with the field.
• Hence, the correct answer is D, "No force".

• The force felt by a moving charged particle in a magnetic field is maximized when the trajectory of the particle is perpendicular to the magnetic field.
• This is due to the nature of the equation F = qvBsinθ, where the force is a maximum for θ = 90 degrees (perpendicular).
• Therefore, the correct answer is B, "Perpendicular to the field".

• In electromagnetism, two parallel currents attract each other while two anti-parallel currents repel.
• Magnetic fields around current-carrying wires are circular, leading to attractions or repulsions.
• The claim that neither attraction nor repulsion occurs is false, hence the correct answer is C, "Neither attraction nor repulsion occurs between two parallel or antiparallel currents".

• Magnetic flux is the measure of the total magnetic field which passes through a given area. It's represented as the product of the area and the component of the magnetic field which passes perpendicular to the area.
• Magnetic flux per unit area (when it's oriented normally) is known either as the Magnetic Flux Density or the Strength of the Magnetic Field or Magnetic Induction (B).
• Therefore, the correct answer is D, "Both A & B".

• It depends on the angle between the magnetic field vector and the area vector to calculate magnetic flux.
• When a plane is parallel to the magnetic field, the angle between the magnetic field and the area vector is 90 degrees. The cosine of 90 degrees is zero, hence the magnetic flux is zero.
• So, the correct answer is A, "Zero".

• When an electron moves within a magnetic field that is perpendicular to its path, the force acting on it due to the magnetic field is also perpendicular to its velocity (F=qvBsinθ). This results in a constant change in direction, but not in the speed of the electron.
• This constant change in direction, without a change in speed, causes the electron to move in a circular path.
• Consequently, the correct answer is A, "Circular".

• Velocity is a vector quantity comprising speed and direction.
• In a straight-line (rectilinear) movement, if an object's speed is unchanging and it moves in a uniform direction, the velocity remains constant.
• However, in a circular or zigzag path, the direction of the object changes continuously, even if the speed is constant, leading to a change in velocity.
• Therefore, the correct answer is B, "Straight-line trajectory".

• Magnetic fields can deflect charged particles such as electrons, protons, and ions during their motion.
• Neutrons, however, do not carry a charge and are therefore unaffected by magnetic fields.
• As such, the correct answer is C, "Neutron".

• In the SI unit system, the unit of magnetic flux is the Weber (Wb).
• Other options: Nm-1 A-1 is the unit of magnetic constant (μ0), Tesla is the unit of magnetic flux density, and Gauss is a non-SI unit for measuring magnetic field strength.
• Thus the correct answer is A, "Weber".

• Magnetic flux density (B) and magnetic flux (Φ) are interconnected through the formula B = Φ / A, where A is the area.
• This implies that the flux density is the total magnetic flux divided by the area through which the flux is taking place.
• Consequently, the correct answer is B, "Flux density equals Flux divided by the area".

• When an electron enters a magnetic field, the direction of deflection will be determined by the right-hand rule.
• As per the rule, an electron (which is negatively charged) will be deflected out of the plane of the paper.
• Thus, the correct answer is B, "Out of the plane of the paper".

          
• The Weber (Wb) and the Maxwell are units used to measure magnetic flux.
          
• Magnetic flux refers to the total magnetic field which passes through a given area.
          
• Hence, the correct answer is C, "Magnetic flux".
      

          
• The standard International System (SI) unit for magnetic induction is the Tesla (T).
          
• While the Coulomb is the SI unit for electric charge and the Curie is a unit for measuring radioactivity, neither is applicable to magnetic induction.
          
• The correct answer, therefore, is B, "Tesla".
      

The magnetic flux through an element of area A in a uniform magnetic field B is typically represented by the formula Φ = B.A (the dot product of B and A).

Therefore, the correct option is B, "Option B".

Charged particles entering a uniform magnetic field, the force on the particle is always perpendicular to its velocity.

As such, the field does not perform work on the particle and the magnitude of velocity—and therefore its kinetic energy—remains the same.

On the other hand, the direction of velocity changes, causing changes in momentum and angular velocity.

Thus, the correct answer is C, "Kinetic energy".

A magnetic field doesn't always exert a force on a charged particle.

Magnetic fields exert force on charged particles in proportion to the sine of the angle between the particle's motion and the magnetic field's direction.

Therefore, if the charged particle is moving across (perpendicular to) the magnetic field lines, it experiences a force.

Hence, the correct answer is C, "Only when the charged particle moves across the magnetic field lines".

While a charged particle moving in a magnetic field, the force acting on it can be defined as F = q (V×B), where q denotes charge of the particle, V denotes it's velocity, and B is the magnetic field.

This formula signifies the cross product of V and B, implying the force is at right angles to both the velocity of the particle and the magnetic field.

Therefore, the correct response is C, "F = q (V×B)".

• A magnetic field affects moving charges, changes in magnetic flux, and currents flowing through a conductor.
• However, a stationary charge doesn't experience any force in a magnetic field. This is because the force exerted by a magnetic field on a charge is given by F = qvB, where q denotes charge, v denotes velocity, and B magnetic field. If v = 0 (for a stationary charge), then F = 0.

• Magnetic fields exert force perpendicular to both particle velocity and magnetic field velocity on moving charged particles.
• This happens due to the cross product in the Lorentz Force equation F = q (V×B).

• Compass needles are simple devices used to detect magnetic fields, such as a magnetic compass.
• It aligns itself with the Earth's magnetic field and is used to understand magnetic fields in general.
• Thus, the correct answer is D, "Magnetized needle compass".

• The unit for magnetic field strength is Ampere per meter (A/m).
• Nevertheless, the Weber unit (Wb) represents magnetic flux, which is calculated by multiplying magnetic field strength (B) with area (A).
• Therefore, Weber ampere per meter is equivalent to Newton (Force), given by the equation F = B (Weber/meter^2) * q * v.
• Hence, the correct answer is B, "Newton".

A magnetic force on an electron beam moving perpendicular to a magnetic field primarily changes the beam's direction.

This is because the force acts perpendicularly, exerting a centripetal force on the beam, causing the electrons to follow a circular path.

Consequently, the accurate answer is D, "The force solely modifies the direction of the electron beam".

Magnetic flux density is measured in Weber per square meter, Tesla, and Newton per (meter times Ampere).

Each of these units is acceptable as an SI unit for measuring magnetic flux density.

Therefore, the correct answer is D, "All of the above".

• The magnetic interaction between two parallel wires will attract them if their currents are in the same direction.
• Each wire generates a magnetic field due to the current flowing through it, and the interaction of these fields results in an attractive force when the current directions align.
• Consequently, the accurate answer is A, "The magnetic force between the two".

• A charged particle follows a circular path when it enters a uniform magnetic field perpendicularly.
• This is due to the magnetic field exerting a force on the particle perpendicular to its direction of motion, causing it to move in a circle.
• Therefore, the accurate answer is B, "A circular path".

• To determine the magnetic field direction produced by a current-carrying conductor, we can use the right-hand rule.
• If your thumb indicates the current direction, then your fingers' curl will show the magnetic field direction.
• Thus, the correct answer is C, "Rotating clockwise".

• When an electron moving along the x-direction encounters a magnetic field in the y-direction, it will be deflected and move in a circular path in the xz plane.
• This happens due to the magnetic force being perpendicular to the velocity of the electron, causing a change in direction but not speed.
• Hence, the correct answer is C, "A circle in the xz plane".

• Generally, magnetic flux density is measured in Teslas (T).
• It represents the force exerted by a magnetic field per unit current per unit length on a current-carrying wire.
• Thus, the correct answer is A, "Magnetic field intensity".

• Magnetic flux is directly determined by the cosine of the angle between the magnetic field and the normal to the area.
• Therefore, the flux is maximum when the angle is 0 degrees.
• Hence, the correct answer is A, "0 degrees".

• The force on an electron moving in a magnetic field is given by F = -eV × B, where e is the charge of the electron, V denotes velocity, and B is the magnetic field.
• Electrons are moving in the opposite direction of the force indicated by the negative sign.

• The magnetic field surrounding a straight wire that carries current forms circular loops around the wire.
• The direction of this field can be determined using the right-hand rule.

• Two current-carrying wires placed in a magnetic field will attract each other if the currents flow in the same direction.
• This is due to the interaction of their magnetic fields.
• Hence, the correct answer is B, "Both are carrying current in the same direction".

• In SI, Tesla (T) represents the force a magnetic field exerts on a wire per unit current per unit length.
• It does not denote electric field strength, electric field intensity, or charge per unit mass.
• Therefore, the correct answer is B, "Magnetic field strength".