Explain the following
a) Although Au is soluble in aqua-regia, Ag is not
b) Zinc and hot copper is used for recovery of Ag from the complex [Ag(CN)2]–

c) Aluminium metal is frequently used as a reducing agent for extraction of metal such as chromium manganese etc.

d) Partial roasting of sulphide ore is done in the metallurgy of copper.

Anonymous User Chemistry Matallurgy 31 Mar, 2020 1 Answer 68 views





A person is to count 4500 currency notes. Let an denote the number of notes he counts in the nth minute.If a1 =a2 =...=a10 =150 and a10, a11,....arein an A.P. with common difference –2, then the time taken by him to count all notes is

Anonymous User Maths Sequences and Series 31 Mar, 2020 1 Answer 56 views









A man saves ` 200 in each of the first three months of his service. In each of the subsequent months his saving increases by ` 40 more than the saving of immediately previous month. His total saving from the start of service will be ` 11040 after

Anonymous User Maths Sequences and Series 31 Mar, 2020 1 Answer 62 views


A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies upto a maximum of 10000 Hz, the maximum value of v upto which he can hear the whistle is

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 59 views


When two tuning forks (fork 1 and fork 2) are sounded simultaneously, 4 beats per second are heard. Now, some tape is attached on the prong of the fork 2. When the tuning forks are sounded again, 6 beats per second are heard. if the frequency of fork 1 is 200 Hz, then what was the original frequency of fork 2?

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 56 views


A tuning fork of known frequency 256 Hz makes 5 beats per second with the vibrating string of a piano. The beat frequency decreases to 2 beats per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 55 views

A metal wire of a linear mass density of 9.8 g/m is stretched with a tension of 10 kg­-wt between two rigid supports 1 metre apart. The wire passes at its middle point between the poles of a permanent magnet, and it vibrates in resonance when carrying an alternating current of frequency u. The frequency u of the alternating source is

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 61 views










A string is stretched between fixed points separated by 75 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. Then, the lowest resonant frequency for this string is

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 57 views




A string is stretched between fixed points separated by 75 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. Then, the lowest resonant frequency for this string is

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 75 views

A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies upto a maximum of 10000 Hz, the maximum value of v upto which he can hear the whistle is

Anonymous User Physics Waves and Sound Waves 30 Mar, 2020 1 Answer 52 views