Electronics Quiz-7
Dear Readers,As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background.
Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced.
(b) In circuit 1, N is connected with N, which is not a series combination of p-n junction. In circuit 2, each p-n junction is forward biased, hence same current flows, giving same potential difference across p-n junction. In circuit 2, each p-n junction is reverse biased, same leakage current will flow, giving equal potential difference across each p-n junction diode.
(a) hfe=((Δic)/(Δib))(Vce=8.2/(8.3-8.2)=82
(D)
Q4. Any digital circuit can be realised by repetitive use of only
(d) NOR and NAND gates are universal gates. Any digital circuit can be realised by repetitive use of these (NOR and NAND) gates.
(a) In p-n junction, the barrier potential offers resistance to free electrons in n-region and holes in p-region.
(b) Pure Cu is already an excellent conductor, since it has a partially filled conduction band, furthermore, Cu forms a metallic crystal as opposed to the covalent crystals of silicon or germanium, so the covalent crystals of silicon or germanium, so the scheme of using an impurity to donate or accept an electron does not work for copper. In fact adding impurities to copper decreases the conductivity because an impurity tends to scatter electrons, impeding the flow of current
(c) Hexagonal close packing is 12 for face centred crystal
(C)
(c) (b) The band width is defined as the frequency band in which the amplifier gain remains above 1/√2=0.707 of the mid frequency gain (A_max). The low frequency f_1 at which the gain fall to 1/√2,i.e.,0.707 times it’s mid frequency value is called lower cut off frequency and the high frequency f_4 at which the gain falls to 1/√2,i.e.,0.707 times of it’s mid frequency is known as higher cut off frequency so band width =f4-f1
(c) When donor impurity (+5 valence) is added to a pure silicon (+4 valence), the +5 valence donor atom sits in the place of +4 valence silicon atom. So it has a net additional +1 electronic charge. The four valence electrons form covalent bond and get fixed in the lattice. The fifth electron (with net -1 electronic charge) can be approximated to revolve around +1 additional charge. The situation is like the hydrogen atom for which energy is given by E=-13.6/n2eV. For the case of hydrogen, the permittivity was taken as ε0. However, if the medium has a permittivity ε_r, relative to ε_0, then E=-13.6/(ε_r2 n2 ) eV For Si,εr=12 and for n=1,E≃0.1 eV
