Physics Test-30

The amplitude of torque is as follows,

\(\Rightarrow[T]=\left[M^{1} L^{2} T^{-2}\right]\)

The dimension of the work is as follows,

\(\Rightarrow[T]=\left[M^{1} L^{2} T^{-2}\right]\)

The amplitude of the momentum is as follows,

\(\Rightarrow[\mathrm{T}]=\left[\mathrm{M}^{1} \mathrm{~L}^{1} \mathrm{~T}^{-1}\right]\)

From the above explanation, it is clear that torque and work have same dimension but momentum has a different dimension.

The third law was developed by Walther Nernst during the years \(1906–12\), and is therefore often referred to as Nernst's theorem or Nernst's postulate. The third law of thermodynamics states that the entropy of a system at absolute zero is a well-defined constant. This is because a system at zero temperature exists in its ground state, so that its entropy is determined only by the degeneracy of the ground state.

In \(1912\) Nernst stated the law thus: "It is impossible for any procedure to lead to the isotherm \(T = 0\) in a finite number of steps."

Power of electric bulb \(=60 \mathrm{~W}\)\(=0.06 \mathrm{~kW}\)

Time used, \(t=6 \mathrm{~h}\)

Energy \(=\) power \(\times\) time taken

\(=0.06 \mathrm{~kW} \times 6 \mathrm{~h}\)

\(=0.36 \mathrm{~kW} \mathrm{~h}\)

\(=0.36\) units.

The energy consumed by the bulb is \(0.36\) units.

Hence, the correct option is (A).

Let the spheres collide after time t, when the smaller sphere covered distance \(x_{1}\) and bigger sphere covered distance \(x_{2}\).

The gravitational force acting between two spheres depends on the distance which is a variable quantity.

Just before the collision, total distance travelled by both \(=9 R\)

If \(x\) is the distance travelled by the block of mass \(M\) and \(9 R-x\) the distance travelled by block of mass \(5 \mathrm{M}\).

As the centre of mass of system, not change, then:

\(M x=5 M(9 R-x)\) \(x=7.5 R\)

Let,

Effective capacitance \(= C\)

Then:

\(\frac{1}{C}=\frac{1}{C_{1}}+\frac{1}{C_{2}}+\frac{1}{C_{3}}\)

\(=\frac{1}{8}+\frac{1}{16}+\frac{1}{24}\)

\(=\frac{6+3+2}{48}\)

\(C=\frac{48}{11} \mu F\)

Potential difference, \(V=110 V\)

We know that:

Charge, \(Q=C V\)

\(Q=\frac{48}{11} \times 10^{-6} \times 110\)

\(=480 \times 10^{-6}\)

\(=48 \times 10^{-5}\)

Since the capacitors are in series each capacitor has the same charge i.e., \(48 \times 10^{-5} C\).

Sugar solutiondoes not conduct electricity.

When sugar is dissolved in water, sugar does not dissociate into ions. Thus, a sugar solution contains only neutral molecules of sugar and water. The neutral molecules do not have any charge and thus, do not conduct electricity. Thus, the sugar solution is a bad conductor of electricity.

Electromagnetic waves or EM waves:

• Electromagnetic waves or EM waves are waves that are formed as a result of vibrations between an electric field and a magnetic field and they are perpendicular to each other and to the direction of the wave.
• An accelerating charged particle produces an electromagnetic (EM) wave.
• A charged particle oscillating about an equilibrium position is an accelerating charged particle.

As we know that EM waves do not have any charge, thus they are not deflected by an electric field and magnetic field. So, option (A) is incorrect.

Electromagnetic waves do not require any matter to propagate from one place to another as it consists of photons. They can move in a vacuum. Thus, option (B) is correct.

Electromagnetic waves or EM waves are waves that are formed as a result of vibrations between an electric field and a magnetic field and they are perpendicular to each other and to the direction of the wave. Thus, option (C) is correct.

The electromagnetic wave moves with the speed of light. Thus, option (D) is correct.

The usual tendency of the charge carriers is to disperse towards the lower concentration region from the higher concentration region. So it can be said that in an unbiased p-n junction, holes disperse from p-region to the n-region as the p-region has a greater concentration of holes than in n-region.