Explanation

- According to Boyle’s Law, at constant temperature, volume is inversely proportional to pressure.

- But if both pressure and temperature increase, the effect depends on which increases more.

- Increasing pressure compresses gases → volume decreases.

- Rising temperature tends to expand gases.

Explanation

Heat of reaction refers to the amount of heat released or absorbed during a chemical reaction.

If heat is released, the reaction is exothermic; if absorbed, it's endothermic.

Explanation

The magnetic force on a moving charge is given by the cross product of velocity and magnetic field.

Its direction is perpendicular to both v and B, following the right-hand rule.

Explanation

Resistivity (ρ) is a material property that measures how strongly a material opposes electric current.

For copper, the standard resistivity at 20°C is approximately 1.68 × 10⁻⁸ Ω·m.

Explanation

In a transistor, the emitter-base junction is forward-biased. 

For a transistor to function properly as an amplifier, the emitter-base junction needs to be forward-biased, allowing current to flow from the emitter to the base. 

Explanation

If two metallic conductors have the same resistivity, they can be differentiated based on their temperature coefficient. 

The temperature coefficient of resistivity indicates how much the resistivity of a material changes with a temperature change.

Materials with the same resistivity can have different temperature coefficients, meaning their resistance will change differently as temperature changes. 

Explanation

The negative gradient of electric potential is called Electric field intensity. 

Gradient:

In general, a gradient represents the rate of change of a function for a given variable.

In the context of electric fields, the gradient of electric potential indicates how quickly the potential changes as you move in a particular direction. 

Negative gradient:

The "negative" part signifies that the electric field points in the direction of decreasing potential. 

Explanation

 If the temperature of the source of heat increases, the efficiency of a Carnot engine will increase.

The efficiency of a Carnot engine is directly related to the temperature difference between the hot and cold reservoirs.

A higher source temperature leads to a greater temperature difference and thus, a higher efficiency. 

Explanation

Explanation

We are given:

• A 30 cm long string
• One end is clamped (fixed), and the other is free to move transversely
• It is vibrating in its second harmonic

We are to find the wavelength of the constituent traveling waves

The allowed standing wave lengths are: L=(n−1/2​) λ​/2 ,for n=1,2,3,…

So:

• 1st harmonic (n = 1):

  L=λ​/4⇒ λ=4L=120cm

• 2nd harmonic (n = 2):

  L= 3λ/4​ ⇒ λ=4L/3​ =4×30/3 =40cm