Which is better for testing ph value? ph paper or ph meter? If so, then why?

Undoubtedly pH meter.

The use of pH paper requires you to visually compare the colour of the pH paper with a colour scale provided by the manufacturer of the pH paper. This means that the determination of the pH point is highly subjective as it depends on your ability to compare colours, a process made all the more complicated by the fact that the colour of the pH paper will never be exactly identical to one of the colours on the scale provided, and therefore you will have to judge that the pH is between 2 values provided on the scale.

On the other hand, a pH meter, once standardised using an unexpired standard pH solution, will give you a pH value correct to one or two decimal places, depending on the model.

The pH meter is very precise but is costly. Paper is cheaper but less precise. It depends on your application which you should use. In my job, certain water samples must be adjusted to a pH of less than 2. For this application, pH paper works just fine. If you need to know the pH of something to 3 decimal places then the meter is the way to go.

It depends on what you want to do and the accuracy that is required. A pH-meter will undoubtedly give you the most accurate measurement. However it requires time to calibrate and a sufficient volume of sample (unless you have a special electrode). Paper with pH-indicators are very fast to use and also you just need to add a drop of your sample on them-this means you can use it for small volumes and you don't insert anything in your sample. There are pH-measuring papers with multiple indicators and thus you can get a very good estimate of pH, even with +/- 0.5 accuracy.

A pH meter definitely. pH meters can give you the exact pH reading of your sample while litmus papers are simply indications whether the solution is acidic or basic. It depends on your usage. Say if you just want to find out if your sample is acidic or basic, use litmus paper instead and spare yourself from going through all the trouble.

pH meter is the best way of determining the acidity or alkalinity.this gives the exact pH value in the digital form provided the meter is properly calibrated.when pH paper is used ,it is compared against the color code values corresponding to a certain pH value.this entirely depends on the visibility of the person and it varies from person to person

It depends on what type of test is it. For simple screening tests like in urinalysis (urine testing), the litmus (pH) paper is very convenient and quite accurate. To simply know the acidity and alkalinity of a solution, the litmus paper is very convenient too, not only these, it is also very practical and quick. The pH meter are usually used in more sensitive solutions, like blood specimens, etc.

a pH meter would be better because it gives you the accurate pH value

while for the pH paper, you have to take note properly the color change before you can consult which pH level it corresponds and one color can range for many levels...so you cannot precisely tell on what the pH level is for a solution

The meter can give a far more precise answer: you just read the number off of a display, instead of having to try to match colors on a chart.