Let E,G and N represents the magnitude of electromagnetic, gravitional and nuclear forces between two electrons at a given separation . Then
ekukfd fdlh fuf’pr nwjh ij fLFkr] nks bysDVªkWuksa ds e/; yxus okys fo|qr pqEcdh;] xq:Roh; rfkk ukfHkdh; cyksa ds ifjek.k Øe'k% E,G rFkk N gS] rks & (a) N < E < G
(b) E > N > G
(c) G > N > E
(d*) E > G > N
Sol.
D Electromagnetic force > Gravitational force > Nuclear force
3.
The sum of all electromagnetic forces between different particles of a system of charged particles is zero.
vkosf'kr d.kska ds fudk; ds fofHkUu d.kksa ds e/; yxusokys fo|qr&pqEcdh; cyksa dk ;ksx 'kwU; gksxk & (a) Only if all the particles are positively charged.
dsoy ;fn fo|qr&pqEcdh; cyksa dk ;ksx 'kwU; gksxk&
(b) Only if all the particles are negatively charged.
dsoy ;fn leLr d.k _.kkosf'kr gSA
(c) Only if half the particles are positively charged and half are negatively charged.
dsoy ;fn vk/ks d.k /kukosf'kr rFkk vk/ks d.k _.kkosf'kr gSA (d*) irrespective of the signs of the charges. Sol.
4.
vkos'kksa ds fpUg ij fuHkZj ugha djrk gSA D Force is a vector quantity is also depend upon direction. A 60 kg man pushes a 40 kg man by a force of 60 N. The 40 kg man has pushed the other man with a force. 60 fdxzk nzO;eku dk ,d O;fDr 40 fdxzk - nzO;eku okys ;fDr dks 60 N cy ls /kDdk nsrk gSA 40 fdxzk nzO;eku dk
O;fDrnwljs dks fuEu cy ls /kdsysxk & Sol.
(a) 40N (b) 0 (c*) 60N Due to action reaction pair they will be equal in magnitude.
(d) 20N
Objective II 1.
A neutron exerts a force on a proton which is
,d U;wVªkWu fdlh izksVkWu ij tks cy yxkrk gS] og gS & Sol.
2.
(a*) gravitional (a*) xq:Roh;
(b) electromagnetic (b) fo|qr&pqEcdh;
(c*) nuclear (c*) ukfHkdh;
AC Neutron is an uncharged particle. Neutron not exerts electromagnetic force on a proton. Only exerts gravitational and nuclear force on a proton. A proton exerts a force on a proton which is
dksbZ izksVkWu] fdlh vU; izksVkWu ij tks cy yxkrk gS] og gS & Sol.
(d) weak (d) {kh.k
(a*) gravitional (a*) xq:Roh;
(b*) electromagnetic (b) fo|qr&pqEcdh;
(c*) nuclear (c*) ukfHkdh;
(d) weak (d) {kh.k
ABC Proton is a charges particle, it can exerts gravitational, electromagnetic & nuclear force on a proton.
manishkumarphysics.in
Chapter # 4 3.
Forces
[2]
Mark the correct statements :
lR; dFku pqfu;s &
(a) The nuclear force between two protons is always greater than the electromagnetic force between them.
(d*) The electromagnetic force between two protons may be greater than the nuclear force acting between them. Sol.
4.
nks izksVkWuksa ds e/; yxus okyk fo|qr pqEcdh; cy muds e/; yxusokys ukfHkdh; cy ls vf/kd gks ldrk gSA BCD Nuclear force is much stranger than the coulomb force when distance between the two particles is less than 10–14 m. So we can say gravitational force & electromagnetic force between two protons may be greater than the nuclear force acting between them. If all matter were made of electrically neutral particles such as neutrons,
(a*) there would be no force of friction. (c*) it would not be possible to sit on a chair (a*) rks ogk¡ dksbZ ?k"kZ.k cy ugha gksrkA (c*) rks ogk¡ dqlhZ ij cSBuk laH ko ugha gksrkA
(b*) there would be no tension in the string (d) the earth could not move around the sun. (b*) rks ogk¡ Mksjh esa ruko ugha gksrkA (d) rks i`Foh lw;Z ds pkjksa vksj xfr ugha djrhA
ABC Earth move around the sun due to Gravitational force.
Which of the following systems may be adequately described by classical physics ?
fuEu esa ls dkSuls fudk; Bhd fpj lEer ;kaf[kdh ds varxZr vkrs gS &
Sol.
6.
(a*) motion of a cricket ball (c) a hydrogen ato (a*) fØdsV dh xsan dh xfr (c) gkbMªkstu ijek.kq
(b*) motin of a dust particle (d) a neutron changing to a proton. (b*) /kwy ds d.k dh xfr (d) izksVkWu esa ifjofrZr gksrk gqvk ,d U;wVªk Wu
AB In the classical physics described the Newton's Laws of Motion, Newton's Law of gravitation, Maxwell's electro-magnetism, Laws of thermodynamics and the Lorentz force. The formulation of classical physics is quite accurate for heavenlybodies like the sun, the earth, the moon etc. For particle much smaller than 10–6 m (such as atoms, nuclei etc.) these rules do not work well. The two ends of a spring are displaced along the length of the spring. All displacement have equal magnitudes. In which case or cases the tention or compression in the spring will have a maximum magnitude ?
fdlh fLizax ds nksuksa fljs fLizax dh yEckbZ ds vuqfn'k foLFkkfir fd;s x;s gsA leLr foLFkkiu leku ifjek.k ds gSA fdl fLFkfr esa ;k fLfkfr;ksa esa fLizax esa ruko ;k laihMu dk ifjek.k vf/kdre gS & (a*) the right end is displaced toward right and the left end towards left.
nk;ka fljk nk;h vksj rFkk ck;ka fljk ck;ha vksj foLFkkfir fd;k tk;sA (b) both ends are displaced towards right.
nksuksa fljs nk;ha vksj foLFkkfir fd;s tk;sA
(c) both ends are displaced towards left.
nksuksa fljs ck;ha vksj foLFkkfir fd;s tk;sA
(d*) the right end is displaced towards left and the left end towards right.
AD In case of tension (expansion) The right end is displaced towards right and the left end towards left. In case of compression The right end is displaced towards left and the left end towards right.
7.
Action and reaction
Sol.
fØ;k rFkk izfrfØ;k &
Sol.
(a*) act on two different objects (c*) have opposite directions (a*) nks fHkUu&fHkUu oLrqvksa ij yxrh gSA (c*) dh fn'kk,sa foijhr gksrh gSA
ABCD
(b*) have equal magnitude (d*) have resultant zero. (b*) ds ifjek.k ,d leku gksrs gSA (d*) dk ifj.kkeh 'kwU; gksrk gSA
