Question
A heating element using nichrome connected to a 230 V
supply draws an initial current of 3.2 A which settles after a few seconds to a steady value of 2.8 A. What is the steady temperature of the heating element if the room temperature is 27.0 °C ?Temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 × 10-4°C-1.Solution
At room temperature 27°C, the resistance of the heating element. R27° = 230/3.2 = 71.875 ohm At the steady temperature t° C, the resistance Rt = 280/2.8 = 82.143 ohm Now, R2 = R1[1 + α(t2 - t1) => 82.143 = 71.875[1 + 1.7 x 10-4(t - 27)] => 0.0840 x 104 = t - 27 => 840 = t - 27 => t = 867°C
A businessman's earning increase by 25%in one year but decreases by 4%in the next. Going by this pattern, after 5 years, his total earnings would be Rs....
In a city, the number of persons travelling by bike is 70% the number of persons travelling by metro. The number of persons travelling on foot is 50% th...
In an examination having total 300 questions, in the first section having 180 questions. A student got 75% marks in first section, but he got 80% marks ...
Aman allocated 40% of his monthly income for purchasing newspapers and then spent 52% of the remaining amount on food, saving the rest. If the amount sa...
A person spent 15% of his monthly income on food and 60% of the remaining on rent. If amount spent on rent is Rs 5798.70, then find the amount spent on ...
In an exam, Sunil scored 46% marks and failed by 65 marks whereas Anil scored 66% marks in the same exam and scored 45 marks more than the passing marks...
If price of grains is increased by 50%, by how much percent a person has to decrease his consumption of grains so that expenditure on grain increases on...
The difference between 7/10 of a number and 38% of the number is 112. What is 20% of the number?
...- Initially, Meena had a salary of Rs. 45,000 and her expenses to savings were in the ratio 5:4. After her salary increase, she spent 10% less and saved 50% ...
If the price of an essential good rises by 18% and the consumer decreases his consumption by 12%, what will be the percentage change in the expenditure?
Relevant for Exams:
