Question: I own about $10,000 worth of Series E savings bonds purchased over the past 30 years or so. I would like to convert these bonds into more liquid assets paying a higher rate of interest, but without paying the income tax on a substantial amount of accrued interest. (I am now in the 50 percent tax bracket.) What do you suggest I do with these bonds?

Answer: The simplest thing you can do is exchange the Series E bonds for Series HH bonds. You can then continue to defer the tax liability on the accrued interest on the E bonds until you redeem the HH bonds--which may be after you retire and are in a lower tax bracket.

However, Series HH bonds pay only 7.5 percent interest in cash on a semi-annual basis and are taxable in the year received.

Your old Series E bonds are doing better than that. From Nov. 1, 1982, through April 30, 1983, they accrued interest at the rate of 11.09 percent. From May 1 through Oct. 1 of this year, the rate will be 8.64 percent.

That's because interest on old Series E bonds that have not yet reached maturity, and on new Series EE bonds, is market-based--set at 85 percent of the market rate on Treasury five-year securities during the previous six-month period.

In order to qualify for the market-based rate, you must hold the bonds until at least the first interest period beginning on or after Nov. 1, 1987 (five years after this new market-based system began).

If you want to convert to a more liquid investment like T-bills, certificates of deposit or mutual fund shares, I'm afraid you're going to have to report and pay tax on all the accumulated interest.

Q: In connection with your tax tip on earned income for husband and wife (May 2), a definition of "earned income" might be helpful. My wife works and I am retired and receive a monthly pension. I think I earned the pension, but does the IRS think so?

A: I don't think there is any doubt that you earned the pension you are now receiving. But the answer implicit in your question is right. For the purpose of qualifying for the tax deduction for a two-earner family, the income of both spouses must be paid for services performed in that same year. Therefore, retirement pay and other forms of deferred income do not qualify.

Q: I have worked in the federal government for the past 12 years, and have contributed close to $20,000 toward my federal retirement. I plan to leave government service soon to work in private industry. If I withdraw my federal retirement money, will it be taxed as ordinary income? Could I roll over the money into my IRA account? Should I leave it where it is?

A: If you withdraw the money you have contributed to the retirement fund when you leave government service, you will incur no tax liability at all for that money. It was taxed as a part of your salary when it was withheld, and you are not required to pay income tax twice on the same funds.

For the same reason, you may not roll that money over into an IRA. A rollover is permitted only for distributed funds originally contributed by the employer.

You'll have to get out your calculator or pencil to figure out whether to leave the money in the retirement fund or withdraw it. The first step is to find out from the personnel office what your accumulated funds will get you in the way of a retirement payout and at what age--and remember that the Reagan administration is talking about changing the rules for retirement.

Then compare those projected numbers with the earnings you think you could generate if you pulled the money out and invested it on your own until retirement time.

I would suggest you consider either a single-premium deferred annuity or a zero-coupon municipal bond, so that you won't have to worry about paying income tax on the earnings as they are accumulating.