TS EAMCET 2019 :: Physics :: General questions

• Physics - General questions

Which of the following represents fundamental force of nature ?

Answer:

Explanation:

There are four types of fundamental  forces in nature namely, (i) Gravitational force (ii) electromagnetic force (iii) strong nuvlear force and (iv) weak nuclear forces

However , other forces like , strong surface tension , weak van der waal's  force, viscous force, etc are the forces which can be derived from these fundamental forces.

The logic circuit below has the truth table same as that of 

Answer:

Explanation:

The truth table for the given logic circuit

The truth  table of the logic circuit  is same as that of NAND gate

The collision of an electron with kinetic energy  5.5 eV and a hydrogen atom in its ground  state can be described as

Answer:

Explanation:

Given, kinetic energy of electron =5.5 eV

The energy required to excite a hydrogen atom  from ground state (n=1) to first excited state (n=2) is 

$\triangle E= E_{2}-E_{1}$ 

=  -3.4-(-13.6)=10.2 eV

 When an electron collids with hydrogen atom in the ground state with energy of 5.5 eV which is less than 10.2 eV , then it will not be able to excite  hydrogen atom into first excited  state. Therefore, electron will not give any energy to the hydrogen atom. Gence , the total kinetic energy  of electron remains conserved . Hence , its collision with hydrogen  atom is elastic

 An  electromagnetic wave of frequency 3.0 MHz passes from vacuum into a  non-magnetic medium with permittivity,  

$\epsilon=16 \epsilon_{0}$ . where $ \epsilon_{0}$ is the free space permittivity. The change in wavelength is 

Answer:

Explanation:

Given , frequency of EM wave 

f=3MHz

= $ 3 \times 10^{6} $ Hz

 and permittivity of non -magnetic medium

 $\epsilon=16\epsilon_{0}$

 Wave length of EM wave,

 $\lambda=\frac{c}{f}=\frac{3 \times 10^{8}}{3 \times 10^{6}}$

$\lambda$  =100 m

Velocity of electromagnetic (EM)  into non-magnetic  material

   $v=\frac{c}{\sqrt{\epsilon_{r}}}=\frac{3 \times 10^{8}}{\sqrt{16}}$     $\left[ \because \epsilon_{r}=\frac{\epsilon}{\epsilon_{0}}=16\right]$

    = $\frac{3}{4}  \times 10^{8}$  m/s

 $\therefore$    Wavelength  ,   $\lambda'=\frac{v}{f}=\frac{\frac{3}{4}\times 10^{8}}{3 \times 10^{6}}=25 m$

$\therefore$   Change in wave length = $\lambda'- \lambda$

  =25-100= -75 m

 An  inductor coil is connected to a capacitor  and an AC source of rms voltage 8V in series . The rms current in the circuit is 16 A and is in phase with emf . If this inductor coil is  connected to 6 V  DC battery, the magnitude of steady current is 

Answer:

Explanation:

Given , 

Rms voltage  of AC source $ V_{rms}=8V$   and the rms current  in the circuit , $I_{rms}=16 A$

 According to the question ,

$\therefore$ impedance of the circuit

 $Z= \frac{V_{rms}}{I_{rms}}=\frac{8}{16}$

 Z=0.5 $\Omega$

 When the inductor coil is  is connected to a 6 V DC battery  then $V_{rms}$'=6 V= $V_{DC}$

$\therefore$   Magnitude of steady current,

 $I'=\frac{V'_{rms}}{Z}=\frac{6}{0.5}=12 A$

• Physics - General questions