SRMJEEE Physics Mock Test - 6 - JEE MCQ

In a helium nucleus, the composition includes:

• 2 protons: These are positively charged particles that define the element as helium.
• 2 neutrons: These neutral particles contribute to the nucleus's stability and overall mass.

Helium does not contain electrons within its nucleus; instead, electrons orbit the nucleus in shells. Therefore, the helium nucleus consists solely of protons and neutrons.

In the hydrogen spectrum, each series has specific upper and lower wavelength limits. The series that has an upper limit of wavelength at 18752 Å is identified as follows:

• The Lyman series corresponds to transitions to the ground state from higher energy levels.
• The Balmer series involves transitions to the second energy level.
• The Paschen series relates to transitions to the third energy level.
• The Pfund series pertains to transitions to the fourth energy level.

Given the wavelength of 18752 Å, this value is characteristic of the Pfund series, as it indicates transitions involving higher energy levels that result in longer wavelengths.

To determine the value of resistance, we can use Ohm's Law, which states:

• V (Voltage) = I (Current) × R (Resistance)

Given:

• Voltage, V = 100.5 volts
• Current, I = 10.2 amps

Rearranging the equation to find R:

• R = V / I

Substituting the values:

• R = 100.5 volts / 10.2 amps
• R ≈ 9.85 ohms

Therefore, the calculated resistance is approximately 9.85 ohms, which does not match any of the provided options.

Ammeter is connected in series always. Ammeter has a very low resistance. So the current which we measure in a circuit using the ammeter will be same as if the ammeter is not there.

So connecting an ammeter in parallel with a circuit means that you just short circuited the circuit you were intending to measure.

        An ammeter has a very low internal resistance. So, if it is connected in parallel with a load, it will short-out that load in resulting a high current flowing through the ammeter may severely damage the ammeter (and possible harm the user), although most are fitted with fuses to protect them.

Correct Statement Analysis:

• Photocurrent is influenced by the intensity of light; it increases with higher intensity.
• The relationship between photocurrent and applied voltage is generally proportional, meaning as voltage increases, so does the photocurrent.
• The frequency of light affects the energy of photons but does not directly increase the current in a photocell.
• The stopping potential is related to the energy of the incident photons, which depends on their frequency, not intensity.

In wave mechanical model momentum is given by λ = h/p. If λ is same then momentum will be same.

nine times

Explanation:

The self-inductance (L) of a coil is given by the formula:

L = μ₀ * n² * A / l

where μ₀ is the permeability of free space, n is the number of turns in the coil, A is the cross-sectional area of the coil, and l is the length of the coil.

When the number of turns in the coil is tripled, n becomes 3n. The formula for self-inductance now becomes:

L' = μ₀ * (3n)² * A / l

L' = μ₀ * 9n² * A / l

Now, let's compare the new self-inductance (L') to the original self-inductance (L):

L' / L = (μ₀ * 9n² * A / l) / (μ₀ * n² * A / l)

L' / L = 9

So, the self-inductance becomes nine times its original value when the number of turns in the coil is tripled without any change in the length of the coil.

Electrostatic energy = Thermal energy

A high voltage capacitor can be dangerous even after disconnection.

• Capacitors store electrical energy, which can remain even when power is cut off.
• Touching the terminals may discharge energy, leading to a risk of electric shock.
• This stored energy can affect dangerously if not properly handled.

Always ensure capacitors are safely discharged before handling to avoid potential hazards.

Venus appears brighter than other planets due to several factors:

• Proximity: It is closer to Earth than most other planets, enhancing its visibility.
• Reflective Atmosphere: Its thick atmosphere is made up of clouds that reflect sunlight effectively.
• Size and Surface: Being relatively large and having a smooth surface contributes to its brightness.

To determine the increase in radiation emitted by a black body when its temperature is raised, we can apply the Stefan-Boltzmann Law.

This law states that the power radiated by a black body is proportional to the fourth power of its absolute temperature (T). The formula is expressed as:

• P ∝ T⁴

To find the increase in radiation when the temperature changes from 27°C to 327°C, we first convert these temperatures to Kelvin:

• 27°C = 300 K
• 327°C = 600 K

Next, we calculate the radiation emitted at both temperatures:

• At 300 K: P₁ ∝ 300⁴
• At 600 K: P₂ ∝ 600⁴

Now, we find the ratio of the two radiation emissions:

• Fractional increase = P₂ / P₁ = (600⁴) / (300⁴) = (600 / 300)⁴ = 2⁴ = 16

Thus, the radiation emitted increases by a fraction of 16.

Resolving the tension in horizontal and vertical direction we get, 
The component along the vertical direction is T cosθ
The component along the horizontal direction is T sinθ
The weight of the string acting in downward direction W = mg.

Let the time period of the buses are T_A, T_B,  angular velocity is ω_A, ω_B and linear velocity is v_A, v_B. We know that for circular motion

According to the question time period is same for both the buses

By the relation of v = ωr 

acceleration = at

Assertion: Magnitude of change in velocity is acceleration due to gravity which is constant throughout the motion.
Reason: Initially acceleration is opposite to the vertical component of velocity which decreases its magnitude till highest point. After crossing highest point acceleration is in the direction vertical component of velocity which decrease magnitude of velocity.
Hence, Assertion is false and reason is true.

Angular momentum of the projectile
L = mv_hr⊥
= m(vcosθ)h (where h is the maximum height)

The instantaneous speed is always equal to the magnitude of instantaneous velocity.
This is because, while calculating instantaneous velocity, the time interval taken into consideration is infinitesimally small.

When the time interval is extremely small, distance is approximately equal to displacement. 
Instantaneous speed = Instantaneous velocity

The position of COM is given by

Net mass is given by

Net force on Axis

Let radius of curvature of the common internal film surface of the double bubble formed be r'. Then, excess of pressure as
compared to atmosphere inside 

The pressure difference is

The expression of capillarity is 

Given,
ɳ = 0.07 kg m⁻¹s⁻¹, dv = 1 ms⁻¹,
dx = 1 mm = 1 × 10⁻³ m,   A = 0.1m²   

Let h be the desired height of liquid in cylinder for which the force on the bottom and sides of the vessel is equal
Force on bottom = ρ gh × πR²
Force on the walls of vessel
= ρ g πh²R = ρ g h π Rh or R = h

Excess pressure  in case of liquid drop,

If r is the radius of small droplet and R is the radius of big drop, then according to question,

Work done = surface tension × increase in area

The force acting on the ball are gravity force, buoyancy force and viscous force. When ball acquires terminal speed, it is in dynamic equilibrium, let terminal speed of ball is v_T.

Terminal velocity is proportional to square of radius of the sphere.
v ∝ r² 

and using volume conservation,

When the waves y₁ = a sin ωt and y₂ = a cos ωt are superimposed, the resultant amplitude can be determined as follows:

• The individual waves have amplitudes of a each.
• When combined, the resultant wave can be expressed as:
• Resultant amplitude = √(a² + a²) = √(2a²) = a√2.
• Thus, the resultant amplitude is a√2.